We take our measure of time in various ways. Days can “drag on” and years “fly by.” We count candles on birthdays and centuries in epochs. Lives are seen as long or short, their perceived volume defined through experience irrespective of length.
Had Moses died at the age of forty, he could have been eulogized as having lived a full life. His obituary in the Papyrus Times could have read something like this:
“Moshe ben ‘Amram was born in the slave camps during the years of Pharaoh’s aggressive family planning program. His parents abandoned him to the Nile in his infancy only to be rescued by the Princess. Egypt’s Hebrew prince was a polymath who excelled in astronomy, architecture, public administration, and military strategy. His conquest of the Ethiopians as general of Pharaoh’s armies is legendary. The Palace will conduct funerary rites in light of Moshe’s station and accomplishments even though Pharaoh had him executed for murder.”
Moses’s next forty years could comparatively be view as somewhat uneventful. He fled from Pharaoh a fugitive, fought off thuggish shepherds in Midian, married a priest’s daughter, and raised a family as he led and fed his father-in-law’s flock. It’s amazing what one encounter with a burning bush can do to a person’s life.
Moses’s last forty years were unarguably his most productive. Talk with the Living God face to face? Check. Transform staff to snake and give yourself leprosy? Check. Confront sorcerers and out-curse them to the catastrophic destruction of Pharaoh’s kingdom? Check. Crack the Red Sea and walk across dry shod? Check. Climb into the fiery Glory Cloud and watch God carve commandments in stone? Check. Celebrate 81st birthday? Check. Spy on giants and plan a conquest? Check. See your people lose heart and hear them grumble against God? Check. Watch an entire generation die while wandering through the wilderness? Check.
Scripture informs us that Moses died at the age of 120, clear-eyed and full of vigor. I have seen young men and old who look longingly toward the day of their departure due to their debilities and trials. Moses didn’t live his life that way. He wanted to cross the Jordan, conquer the “ites,” and live in the Promised Land. Even so, in the trying wilderness years he sang this sage psalm.
10 The years of our life are seventy, or even by reason of strength eighty; yet their span is but toil and trouble; they are soon gone, and we fly away.
11 Who considers the power of your anger, and your wrath according to the fear of you?
12 So teach us to number our days that we may get a heart of wisdom. ESV
We need the Lord‘s instruction to correctly count the days of our lives. Each one we are given is precious and irreplaceable. Because of the eternal irony, we can easily lose sight of this. We were created to live forever and designed to die. Our hearts are often blind to mortality even as our bodies decay.
He has made everything beautiful in its time. Also He has put eternity in their hearts, except that no one can find out the work that God does from beginning to end. NKJV [Emphasis added.]
Our hearts hold the sense of the eternal and wonder at the works of God. He created us this way in order to teach us of His power and divinity. Nevertheless, He made our flesh in such a way that it could not avoid decay without His sustenance.
Genesis 2:8-9, 16-17
8 And the Lord God planted a garden eastward in Eden; and there he put the man whom he had formed.
9 And out of the ground made the Lord God to grow every tree that is pleasant to the sight, and good for food; the tree of life also in the midst of the garden, and the tree of knowledge of good and evil.
16 And the Lord God commanded the man, saying, Of every tree of the garden thou mayest freely eat:
17 But of the tree of the knowledge of good and evil, thou shalt not eat of it: for in the day that thou eatest thereof thou shalt surely die. KJV
Adam’s original instruction set contained directions on how to live, and how not to die. Living entailed eating the freely given fruit from the trees, especially the tree of life. Not dying was as simple as denying the desire to dine on the tree of knowledge of good and evil. We’ve all been to funerals. We know Adam did the very thing they weren’t supposed to do. Before we dig up the details on the timing of his death, let’s look at the start of his fallen life.
21 Unto Adam also and to his wife did the Lord God make coats of skins, and clothed them.
22 And the Lord God said, Behold, the man is become as one of us, to know good and evil: and now, lest he put forth his hand, and take also of the tree of life, and eat, and live for ever:
23 Therefore the Lord God sent him forth from the garden of Eden, to till the ground from whence he was taken.
24 So he drove out the man; and he placed at the east of the garden of Eden Cherubims, and a flaming sword which turned every way, to keep the way of the tree of life. KJV
In testimony of His plan to redeem man through the blood of Jesus, God made sacrifice in the garden and clothed His children in the skins of the slaughtered cattle. But note the Godhead’s discussion regarding the tree of life in verse 22. Even while dead in trespass and sin, Adam and Eve could have physically survived forever on the fruit from the tree of life.
This same tree will provide healing and life-sustaining food in New Jerusalem when the curse is no more.
1 And he shewed me a pure river of water of life, clear as crystal, proceeding out of the throne of God and of the Lamb.
2 In the midst of the street of it, and on either side of the river, was there the tree of life, which bare twelve manner of fruits, and yielded her fruit every month: and the leaves of the tree were for the healing of the nations.
3 And there shall be no more curse: but the throne of God and of the Lamb shall be in it; and his servants shall serve him: KJV
What biology calls “programmed cell death” is God’s design for physical life. Even in our current decrepit state, the rate of cellular production, proliferation, and replacement is astonishing. What we now call aging is the slowdown and final failure of this process. The mortality of our flesh is by design.
It is in the light of this eternal irony—hearts made for boundless time housed in bodies inclined to die—that we are to take pause and pray the Lord teach us to count our days aright and gain wisdom.
 For example, see the description of Abraham’s life (Gen. 25:7-8) as compared to Jacob’s (Gen. 47:8-9).
 Moses’s accomplishments while a prince of Egypt are alluded to by Stephen (Acts 7:22). See also Flavious Josephus, The Antiquities of the Jews, 2.10.
 Deut. 34:7.
 Rom. 1:20-21.