Psalm 90 is a unique psalm because it is attributed to Moses. We do not think of Moses as a songwriter, however, there are a couple of songs that are attributed to him (Exodus 15; Deuteronomy 32). One scholar suggests that Psalm 90 was written after the traumatic events of Numbers 20. In Numbers 20 there are three painful events in Moses’ life: (1) The death of Miriam, (2) Moses’ sin of striking the rock, and (3) The death of Aaron. Moses loses his sister and his brother and also loses the right to enter the promised land because of his sin. Perhaps these are the circumstances that cause reflection in Moses’ song and prayer to God.
The Eternal Grandeur of God (1-2)
The psalm begins with recognition of God as a refuge and dwelling place for His people in every generation. Then Moses praises God for His eternal nature. Verse 2 states a fact that is hard for humans to wrap their minds around. Before there were mountains and before there was an earth, God existed. From eternity to eternity there is no beginning or end to God. This is difficult because everything we know in life is temporal. Everything has a beginning and an end. So we have to remember that God is eternal. God has seen it all and is able to see all things to know what is best for us.
The Frailty of Humanity (3-12)
The eternal nature of God is contrasted with the frailty of humans. While God endures forever and ever, we return to the dust of the earth. A familiar statement is found in verse 4:
For a thousand years in your sight are but as yesterday when it is past, or as a watch in the night.
This is merely a statement about how time is inconsequential to God. While everything in our life is dictated and controlled by time, God is not constrained by such concerns. Our work, our sleep, our eating, our schooling, and everything else in life is complete controlled by time. It is hard to think of a being that is not controlled by time. That is the point of Moses’ statement. Thousands of years are meaningless to God while to humans thousands of years are immense. The apostle Peter was trying to make the same point to his readers in 2 Peter 3:8,
But do not overlook this one fact, beloved, that with the Lord one day is as a thousand years, and a thousand years as one day.
Please note the point that both Moses and Peter are making. The point is not to use this as a definition for interpreting the scriptures. The point is to help us grasp the eternal nature of God. God is not bound or constrained by time. The point Peter was making is that humans should not think that God is slow concerning his promises because God is not bound by time. We think it has been a long time for God’s promises to be fulfilled, but God does not operating within such time constraints. God is eternal and will not be forced to act simply because our lives are short. With Moses, he is simply contrasting our nature of being bound by time against God who is eternal and not bound by time.
The point about our temporal nature is clarified in verses 5-6. Humans are here one day and gone tomorrow. The images Moses uses to picture this brevity are vivid. We are like new grass that sprouts up, but under the heat quickly dies. This is what happened to our grass when we built our house. We put in new grass, went on vacation for a couple of weeks to California, and came back with grass that was weak and has never been able to fully recover. The other image Moses uses is morning and evening. Our lives are so short it is like a morning and evening against the eternal nature of God. We would like to think that we have an eternity of life ahead of us. Frequently we live our lives as if there is no end in sight. Such living is foolishness.
Moses goes on to talk about the frailty of humanity in light of our sins. Moses points out that our sins are linked to death. Our mortality traces back to judgment for our sins. Our sins stand before God. Our hidden sins are brought to light in God’s presence. How often we think that God is not aware of our sins! How often we think that we are not going to pay a penalty for our sins! But Moses reminds us that our sins are very visible to God.
Moses goes on to talk to about the brevity of our lives. In verse 10 Moses tells us that 70 years of life is to be expected and 80 years if we are strong. Yet these years are years of toil and trouble. But soon our days are gone and we are gone. None of us really like to think about the brevity of life. However, God wants us to be mindful that this is not all that there is to life. Our time is short to serve God and then be held accountable for our actions.
Yet you do not know what your life will be like tomorrow. You are just a vapor that appears for a little while and then vanishes away. (James 4:14)
Verse 12 tells us the point of why we need to think about the brevity of life. We need to number our days so that we will learn to live wisely. When we think we have all of the time in the world, we will make foolish or wicked decisions. We neglect our family assuming that we have loads of time in the future to our enjoy our families. We neglect God thinking that we can return to him later. We plunge ourselves into sinful living thinking that there will always be time to repent. Jesus’ parable of the rich fool in Luke 12 is very appropriate for our consideration. When we think we have our whole lives ahead of us is when we act like the rich fool who is only concerned about “building bigger barns.” Little did he think that very night his life would be required of him. Because our lives are short, we need to make the most of our time, taking advantage of our opportunities to draw closer to God. As Christians, we should know to not assume that we have tomorrow.
Requesting God’s Favor (13-17)
The final section of this psalm is Moses’ request for God to return his favor to him and the people. As we have seen in some of the last few psalms, the request centers around God’s steadfast love. The first request of Moses was that we be taught to number our days. The second request is that we will be satisfied with God’s faithful love. The void that we try to fill in our lives in seeking after God. We use possessions and wealth to try to fill the void. But the clamor will only find fulfillment with God. Trying to find happiness and satisfaction in other places will leave you empty. Christians have to be different than the world, particularly when we are talking about where we find our satisfaction. We should not look like the world when it comes to find joy in the physical things of the world. Our joy and our satisfaction must be in the Lord. We show that we have that joy by worshipping God, enjoying reading and studying our Bibles, and enjoying prayer. When we place a greater importance on after-school programs, extracurricular activities, sports, work, or anything else, we are not Christians finding their satisfaction in the Lord.
The final request of Moses is that the Lord establish the work of their hands. This places a responsibility on our part to live our lives in such a way that God can approve of our actions and establish our works. We cannot ask God to uphold and establish what we are doing in our lives if we are living sinful lives. We cannot ask God to be with our works when we are not actively seeking the interests of God above our own. Moses was a great example of putting the interests of God ahead of the interests of himself. Moses suffered much for the cause of the Lord. Moses left the riches of Egypt to live in the wilderness of Midian. Moses suffered the scorn of his own people who he was trying to deliver from slavery. Moses endured the criticisms of the people and the murder attempts on his life as they walked through the desert to the land of Canaan. But Moses was established by God because he trusted fully in the Lord through victories and through the difficulties.