I had a little fun with the title because this is a “heavy” subject, and I wanted to lighten things up a little. And while we’re at it, what in the world is Moses wearing; it looks like a costume. (At least there’s not a big “M” on his chest.)
Okay, back to our serious topic. . .
One of our pastors recently preached from Psalm 90. I was particularly struck by one of its most well-known (and sobering) verses—verse 12:
Teach us to number our days, that we may gain a heart of wisdom. (ESV)
This Psalm is actually a prayer of Moses. (I had no idea that anything Moses said, wrote, or prayed was included in the Psalms.) Like most people, I assumed they were all written by David and a few others. But there it is—a Psalm of Moses. (It is the only one in the Book, by the way.)
Could Moses sing? He was quite the choirmaster (see Ex. 15, Deut. 31-32, and Rev. 15:3-4).
In any case, Moses, reflecting on the fleeting nature of life, urges us to live with an awareness of our mortality—our days are numbered.
When we think of our “future selves,” we rarely, if ever, consider our future “deceased selves.” I don’t want to be too morbid about this, and that’s as nicely as I could say it, But remember—we’ll continue to exist, albeit in spiritual form, for a while until we get our new resurrected bodies. As Herman Bavinck wrote,
On the basis of the perfect work of Christ, therefore, heaven stands open for the believers immediately upon their death. . . Although the believers upon their death immediately become sharers of the heavenly blessedness according to their soul, still their condition is in a certain sense still a preliminary one and a still imperfect one. After all, their bodies are still in the grave and are there subject to decay; soul and body are still separated and do not share in the eternal blessedness in union with each other. (Herman Bavinck, The Wonderful Works of God, p. 772-773)
Perhaps that’s one of the reasons why this can make us so uncomfortable. We have a natural aversion to what Moses calls us to do—contemplate the finitude of our existence on this planet. We all enjoy being in our bodies, and it’s hard to imagine not having one, even for a while.
Numbering our days
When Moses wrote that verse, I don’t think he was suggesting that we sit down and add up the number of days we’ve lived and the number of days until we die. It’s more of a figure of speech that affects our hearts and minds.
We can’t literally “number our days” into the future, only those in the past. Even though our days are indeed numbered, we don’t know how long we will live—only God does. He is sovereign over all, including our lifespans.
The Bible—especially the Old Testament—affirms that God has determined the length of our lives down to the days and hours. Consider Job 14:5:
“Since his days are determined, and the number of his months is with you, and you have appointed his limits that he cannot pass.” (ESV)
Jesus also spoke of this in Matthew 6:27:
“And which of you by being anxious can add a single hour to his span of life?” (ESV)
A “first principle” is that God has determined and set a limit to our days; we can’t live forever in our fallen, mortal state. This is the tragic consequence of Adam and Eve’s sin, recorded in Gen. 3:1-7. God warned them in Gen. 2:16-17 that disobedience would cut their lives short.
It seems that God originally intended for humanity to live forever, which may explain why death feels so “wrong” to us. But due to the curse of sin, our earthly lives are limited.
For this reason, there are limits (boundaries, if you wish) to how long people will live. And God has set a boundary on the length of each of our lives, which was determined before we were born:
“Your eyes saw my unformed substance; in your book were written, every one of them, the days that were formed for me, when as yet there was none of them.” (Psalm 139:16, ESV)
So, we “number our days,” perhaps literally in the past, but more as a Godward state of heart and mind for those that remain in our future.
Numbering our days with stewardship
This blog concerns retirement stewardship: our time, talents, and treasure. I focus mainly on “treasure” (i.e., financial stewardship), but I also delve into time and talents—they’re all important.
In the context of financial stewardship, “numbering our days” is a very relevant concept, even though Moses didn’t specifically have that in mind. He wanted us to grow wiser because our choices during our brief stay on this planet have both temporal and, most importantly, eternal consequences.
In addition to making the best use of today (Eph. 5:15-17), another aspect of “numbering our days” is knowing that each of us only has so many days ahead of us. And the older we get, the more urgency we bring each day as we endeavor to steward it well.
And then there’s the role that “numbering our days” plays in wise financial stewardship. Practically, this is where actuarial science and life tables come in.
Numbering our days with actuarial life tables
Scripture is clear that we will all die one day and that none of us can be sure when. However, a relatively new discipline—actuarial science—uses sophisticated mathematical models to predict death probabilities based on factors like age and health.
Investopedia defines actuarial science as follows:
“Actuarial science is a discipline that assesses financial risks in the insurance and finance fields, using mathematical and statistical methods. Actuarial science applies the mathematics of probability and statistics to define, analyze, and solve the financial implications of uncertain future events. Traditional actuarial science largely revolves around the analysis of mortality and the production of life tables, and the application of compound interest.”
An (actuarial) life table can be further described as a table that,
“. . . displays the probability that a person of specific age will die before their next birthday. The tables are in spreadsheet form and essentially demonstrate the probability of death for each age group within a population. In the long term, the table can also be utilized to explain mathematically the measurement of a population’s longevity in terms of their lifetime before death.”
Actuarial life tables predict and express a particular kind of risk. In the context of our ”number of days,” they’re based on the certainty that we will all eventually reach the end of our lives on this earth.
However, while actuarial life tables cannot predict individual outcomes with certainty, they provide a helpful statistical framework for understanding life expectancy and financial planning, especially for life insurance and long-term annuity payouts.
The Christian Origins of Actuarial Science
You may be surprised to learn that Christians were among the first in modern history to apply actuarial science to financial planning.
In Great Britain, the Scottish Ministers’ Widows’ Fund was created in 1743 to financially support the widows and children of Church of Scotland ministers.
Similarly, in 1759, the Presbyterian Ministers’ Fund in Philadelphia became one of the earliest life insurance organizations in the United States. Initially, its primary purpose was to provide financial relief to impoverished Presbyterian ministers and their families. Over time, it incorporated actuarial principles, using life tables by 1845 to predict mortality rates and financial needs.
Actuarial Science and Theology
Mathematics is a wonderful gift from God. Whether simple or complex, it can help us better understand and describe the well-designed and ordered universe he has created.
Actuarial science, which is mainly based on math, endeavors to consistently predict death probabilities based on factors like age and health. It is a rational discipline grounded in statistical predictability, which aligns with the biblical principle that God has “numbered our days.”
However, that does not mean God cannot intervene in a particular life to shorten or extend it if he chooses (Proverbs 3:1-2). While some people live unusually long or short lives (i.e., some die at birth and others live to be 100+), most fall within a more predictable “normal” statistical distribution.
For example, Social Security used actuarial predictions in its Longevity Visualizer tool (for Windows only) for its 2015 report to its Trustees to show that a 62-year-old man in 2016 wanted to know to what age he had only a 10% chance of surviving.
According to their predictive model, he had a 50% chance of making it to age 84 and only a 10% probability of living beyond age 95. (The estimates are probably higher for a 62-year-old today due to increased longevity.)
I ran my numbers using a newer Social Security online tool:
86 years old; that’s not too bad, I’d take it. Of course, my “days are numbered,” and I have absolutely no way of knowing if it’s 13.9 more years or not. It could be more or less.
In biblical times, people lived much longer than today. Moses lived 120 years (Deut. 34:7), Abraham 175 years (Gen. 25:7), Isaac 180 years (Gen. 35:28), and Jacob 147 years (Gen. 47:28). Outliers like Methuselah reached 969 years (Gen. 5:27). Have you ever wondered what you would do with your time if you lived to be a thousand? (You probably wouldn’t retire at 65.)
If such lifespans were typical today, actuarial science would be upended! But God does sovereignly act on individual lives and, at times, in families, communities, and even nations.
You may remember the story about King Hezekiah in Isa. 38:1. He was about to die, and the prophet Amoz told him he would:
In those days Hezekiah became sick and was at the point of death. And Isaiah the prophet the son of Amoz came to him, and said to him, “Thus says the LORD: Set your house in order, for you shall die, you shall not recover.”
But then the king made his plea to God, and God added fifteen years to his life:
Then Hezekiah turned his face to the wall and prayed to the Lord, and said, “Please, O Lord, remember how I have walked before you in faithfulness and with a whole heart, and have done what is good in your sight.” And Hezekiah wept bitterly. Then the word of the Lord came to Isaiah: “Go and say to Hezekiah, Thus says the Lord, the God of David your father: I have heard your prayer; I have seen your tears. Behold, I will add fifteen years to your life. I will deliver you and this city out of the hand of the king of Assyria, and will defend this city. (Isa. 38:2-3, ESV)
In particular cases like this, divine intervention would likely be statistically undetectable by actuarial scientists.
A reasonable question is whether we can reconcile God’s sovereign control over lifespans with actuarial mortality predictions.
Scripture does not claim God is unpredictable in determining lifespans—though it may seem so to us because some die earlier than expected and others live longer. While we cannot predict an individual’s lifespan, actuarial science can reliably estimate mortality in large groups using mathematical patterns that do not contradict God’s sovereignty.
People die statistically because God has numbered our days within a general range, which he obviously can change. Though actuarial models are helpful, they are not absolute and must be refined over time based on new data, regulations, and risks.
Practical Applications for Retirees
Many commercial and governmental entities use actuarial science for risk-mitigation purposes, particularly concerning retirees. This has lots of practical implications for retirees.
Insurance and annuities
Insurance company actuaries use highly sophisticated statistical models to predict how long those in their ”risk pools” are likely to live. They use actuarial pools to determine the premiums for life insurance policies by analyzing mortality rates or calculating the funding required for annuity payouts by predicting future retiree lifespans and economic conditions.
For example, in the ”mortality table” below, a 40-year-old person has a 0.1% probability of dying within one year, with a corresponding life expectancy of 40 more years. A life insurance firm issuing a policy would use this data (and other factors) to calculate life insurance premiums, ensuring adequate coverage and financial stability.
Given a policy payout of $500,000, the company employs the expected value formula to calculate a fair premium:
EV = P x V
Where P is the probability of death (0.001), and D is the death benefit ($500,000), resulting in an expected value calculation:
EV = .001 x $500,000 = $500
Thus, $500 is a reasonable premium because this actuarial assessment helps set it at sustainable levels, balancing fair customer pricing with company risk.
Insurance companies also use actuarial science to manage their long-term financial obligations to policyholders. Actuaries design payout schemes for different principal amounts based on longevity and investment risks to ensure that customers receive adequate income while managing the risk of fund depletion.
For example, someone who annuitizes their principal at age 80 will receive a much larger payout than someone who starts at 60.
Property insurance premium calculations don’t use mortality tables but actuarial analyses to assess the likelihood and cost of events like natural disasters to help set rates and ensure sufficient reserves are available for claims.
Social Security and RMDs
The IRS and Social Security rely on actuarial science to inform and guide their policies and operations.
I have recently been writing about RMDs. The IRS requires retirees with tax-deferred accounts to start taking Required Minimum Distributions (RMDs) at a certain age—currently, 73.
The RMD tables assume a different “number of days” based on your age, affecting how much you have to withdraw. They do this by setting a ”distribution period for each age. For example, in 2025, when I turn 73, the ”distribution period” is 26.5 years:
They develop these numbers based on life expectancy estimates derived from actuarial studies. This doesn’t mean that the IRS predicts I will live to be 99.5 years old (and I probably won’t).
This means that actuarially speaking, the IRS is using a mathematical approach that balances withdrawal rates and longevity risk to ensure that couples, where at least one of them does live longer, won’t deplete their funds too early due to RMDs. At the same time, the IRS still meets its tax collection goals.
Social Security, on the other hand, uses actuarial models to estimate life expectancy and determine benefits payouts. These models help the Social Security Administration set retirement age thresholds and calculate monthly benefits to ensure the system remains sustainable for future generations.
Below is a Period Life Expectancy Table used by the SSA. For the SSA’s purposes, they use a predictive model that says that an ”average” male born between 1950 and 1955 might expect to live to age 78 if he makes it to age 65, generally when most people have historically started receiving Social Security benefits.
As the report containing the table says,
“Life expectancy, or the average remaining number of years expected before death, is another way to summarize the Trustees’ mortality assumptions.”
In other words, they use these estimates, among other things, to determine how quickly the Soc. Sec. trust fund might be depleted, and how much will be needed to keep it solvent.
What to do with this
You may be thinking, “I already knew that God numbers my days, so what’s the point?” And Psalm 90:12 isn’t about actuarial science; it’s about knowing our days are numbered and gaining wisdom.
The point is that it is wise to consider the simple truth that God is eternal and we are temporary. He is from “everlasting to everlasting;” we are like new grass in the morning that withers by the afternoon.
We need godly wisdom to live intentionally, invest our lives in what truly matters, and prepare for both the temporal and the eternal.
I also thought it’s pretty cool that, when you really think about it, standard actuarial tables, with their reliance on mathematical modeling, point to the direct relationship between God and the divine order he has established that can be partially understood with math.
Actuarial tables can help us number our days in practical ways.
If you’re 50 or 60, looking at one may encourage you to better plan for the future. Looking at an actuarial table at age 70 or 80 may remind you to care for your health, cherish your friends and families, and live each day for the furtherance of God’s kingdom.
Understanding how actuarial science and government policies “number our days” is important to retirees because it gives us a perspective on why our RMDs are what they are, why our Social Security benefits are lower or higher depending on when we claim benefits, and what makes certain types of insurance products appropriate for some people.
Actuarial science provides us with valuable tools, but no matter what it tells us about the likely limits of our lives, none of that matters nearly as much as the satisfaction and joy that come from living a life of love, purpose and hope, peaceably under God’s sovereign care.
May the God of hope fill you with all joy and peace in believing, so that by the power of the Holy Spirit you may abound in hope. (Rom, 15:13, ESV)
