So teach us to number our days, that we may apply our hearts unto wisdom.

Psalm 90:12

Are you numbering your days?

We must number the days of our lives already lived. How old are you? How many days has that been? And what has filled those day?

We must also number the days that we can reasonably expect to live yet on the earth.

It is good to do this that we may apply our hearts unto wisdom.


What it means to number or count our days will become clear only in light of what has already been said in this Psalm concerning the life of man. This Psalm was written by Moses as Israel wandered in the wilderness under the chastening wrath of God. The theme of this Psalm is the frailty and brevity of human life. How short and harsh is man’s life.

Moses describes the brevity of human life in different ways. Man is carried away as in a flood, emphasizing the abrupt ending of man’s life. Man’s life is as a sleep, emphasizing that it is very short and fleeting. How quickly the night passes when we sleep! Man is as the grass so that he flourishes only for a short while. The grass grows up in the morning and flourishes; in the evening it is cut down and withers.

This brevity of life is due to God’s wrath upon sinners. God has set our iniquities before Him. He even sees our secret sins that are known only to us. And God’s wrath is upon us for those sins. In His wrath He brings trouble and sorrow. All our days are passed away in God’s wrath. The days of our years are seventy in number, and if we are strong, eighty. Yet even the strength of those years, which is the best part of our years, is trouble and sorrow. We are soon cut off and fly away.

To whom does this all apply?

It certainly applies to the world in general that lives in unbelief. The world of natural man is depraved and wicked. God has set their iniquities before Him. And in His wrath God punishes them. In wrath He not only brings a quick and abrupt end to their life but also brings them trouble and sorrow in that life. This is only a preparation for the eternal punishment of hell.

What Moses wrote in this Psalm applied primarily to the nation of Israel whom Moses was leading through the wilderness.

Israel was very rebellious against the Lord during their wilderness wanderings. They rebelled against Him at Mt. Sinai by worshiping the golden calf. They rebelled against Him at Kadish-Barnea by believing the report of the ten spies, and thus were sent to wander in the wilderness under the sentence that all those over twenty years of age would die in the wilderness. They continued their sinful rebellion throughout their wilderness wanderings. They served idols, committed fornication, all the while murmuring against Moses and against God. The result was that God destroyed many of them with plagues, fire, and serpents. Indeed, Israel felt the sting of God’s wrath upon them for their sins.

Only we must bear in mind that Israel was the church and not the world, so that God’s dealings with Israel were different from His dealings with the world. In Israel there was a large carnal, reprobate element. The harsh and brief life they experienced in the wilderness was God’s wrath to punish and destroy them for their sin. But the heart of the nation was the elect of God. For them the harsh and brief life of the wilderness was the wrath of God to chasten and correct so that the nation might enter the promised land.

What was true for Israel is also true for the church of all ages. Bear in mind that Israel wandering through the wilderness of the Sinai peninsula was a type of the church of all ages wandering through the wilderness of this world. Also in the church of the ages are a twofold seed, as in Israel. There is the carnal, reprobate seed that live only in sin. But there is also the elect remnant, who in weakness also often rebels against God, wandering away into idolatry as Israel of old did.

And the church’s sins are ever before God so that she also lives under the wrath of God, as did Israel. In the case of the reprobate, this wrath is the punishment of God designed to destroy. In the case of the elect, this wrath is chastisement designed to correct and save. Even the holiest of men have only a small beginning of obedience. Sin follows and taints their lives daily. And their sins anger the Lord. Out of love He corrects them with the rod of chastisement. Certainly not all that they suffer is the direct result of some sin they have committed. God also sends suffering for them to grow spiritually. But every child of God suffers under the chastening wrath of God for sin. According to Hebrews 12:6, 8 the Lord chastens and scourges every son whom He loves and receives. Those who are without chastisement are not His sons.

In this context the Word of God speaks of numbering or counting our days.

To number your days means, first, that you count the days that you have lived. How old are you? How many days is that? Included in counting your days is that you take note of the trouble and sorrow that comes on account of sin.

Consider the sins of the fallen world in which we live and the terrible judgments of God’s wrath upon them. How our society has developed in sin over the past several decades! What terrible punishment God’s wrath has brought upon this sin! The cases of depression and numbers of suicides are growing at an alarming rate. Countless lives are ruined through addiction. Disease spreads through sexual promiscuity. Interestingly, God also punishes sin with greater sin, sin that brings greater and greater misery to sinful man. Marriages fail, homes are broken up, war between the races and nations breaks out and, worst of all, God brings man to the great shame of abounding in homosexuality. As we number our days, we must take note of how the Lord punishes the sins of the world in His wrath.

But in our numbering of days, we must above all consider how the Lord has chastened us for our own sins. It is necessary for the Lord to bring His chastening rod on all of us. And sometimes to teach us the seriousness of sin that chastening continues for a lifetime. Think how God chastened David for his sin against Bathsheba and her husband Uriah. The sword never departed from his house to remind David not to take sin lightly. In the numbering of our days we must take all these things into account.

But to count our days also means that you count how many days you probably have left in your life. The Lord can take our life at any time. But the norm is 70 to 80 years. How many of these years do you have left? As we count these, we see that our life is short and quickly cut off. And soon we will stand before the Judge of heaven and earth.

We must number our days that we may apply our hearts unto wisdom.

Wisdom is the ability to act according to reality so that we prosper. This is in distinction from foolishness, which is to ignore reality so that we flounder.

But we must be more specific. The reality with which we are confronted in this Psalm is God’s wrath, which manifests itself in the brevity and misery of life. In that situation wisdom is to live in daily repentance, turning from sin unto God in Jesus Christ. This repentance involves a humble recognition of our sinfulness. Then there is a godly sorrow over sin, a sorrow that sin has offended God and done injury to the neighbor. Repentance also includes a confession of sin to God and seeking forgiveness in the blood of the cross. And finally, there is a life of grateful obedience to God in the power of Jesus Christ. This is wisdom. This is living in harmony with the reality of God’s dealing with sin. This is the only way to escape God’s wrath on our sins and enjoy the riches of His gracious blessing.

Foolishness is the opposite of this. Foolishness is to continue in sin without repentance, with the result that we either perish under God’s wrath, which is the case with the reprobate, or we receive more stripes of chastisement until finally we turn from sin unto God.

Moses speaks of applying our hearts unto wisdom. More literally he speaks of having or obtaining a heart of wisdom. A heart of wisdom is a wise heart, a heart full of wisdom. Such a heart leads one to act wisely, turning from sin unto God in Jesus Christ. Do you have such a heart of wisdom?

The purpose of numbering our days is to obtain such a heart of wisdom.

We are so inclined to foolishness or a foolish heart. We live daily with the reality of God’s wrath on mankind for its sin and God’s anger with our own sin. Yet so often we are inclined to ignore it all to continue blissfully in our sinful ways. In verse 11 Moses points to this tendency, “Who knoweth the power of God’s anger?” By the power of God’s anger is meant God’s anger as it brings misery to man’s life and destroys him in death after only a few years. This is a rhetorical question. It emphasizes that very few see the connection between the brevity of life and God’s anger on sin. They find trouble and sorrow. They experience the fleeting character of life. But foolishly they refuse to see this as God’s wrath and judgment upon sin. And so the majority blissfully continue in their sinful way.

This is true also for many believers who stagger under the chastisement of God! The unbelief that every true believer still retains tends to blind him from seeing this reality. The chastening rod of God’s love has laid many strips upon his back to correct him. But he will not acknowledge what God is doing. Instead of humbling himself before God in repentance, he may even rebel against God’s dealing with him so that he increases in sin. What folly!

And so Moses instructs us to count our days so that we will obtain a heart of wisdom. To acquire a heart of wisdom requires that we count the days of our past, paying attention to the wrath of God upon the world and even upon us in His chastisement of our own sins. It also requires us to consider the days of our future. How few they are in number. And soon we will be required to give account of ourselves before the Judge of heaven and earth.

Teach us to number our days.

This is a prayer that the Lord teach us to number our days in such a way that we obtain a heart of wisdom. This was Moses’ prayer for Israel. It must be the prayer of each of us for the church and for self.

To number our days correctly is something that the Lord must teach us. He teaches us through His Word. This is the Word brought faithfully from the pulpit on the Lord’s Day. It is the Word brought to covenant youth in their homes and Christian schools. It is the Word that the elderly saints have come to know by experience and that they share with those less experienced in the church.

Pray to be taught.

In prayer turn to the instruction of God’s Word. In the power of God’s Word so number your days that you may apply your heart unto wisdom.