David Chakranarayan, AiG–US, explains why the Bible seems to contradict itself in Genesis and Psalms when speaking about the expected lifespans of individuals.
And the Lord said, “My Spirit shall not strive with man forever, for he is indeed flesh; yet his days shall be one hundred and twenty years.” (Genesis 6:3)
The days of our lives are seventy years; and if by reason of strength they are eighty years, yet their boast is only labor and sorrow; for it is soon cut off, and we fly away. (Psalm 90:10)
The supposed contradiction in these two verses has to do with the length of a person’s life on earth, namely their total years of existence. The passage in Genesis seems to indicate that a human being will not be able to live beyond 120 years of age, but the passage in Psalms seems to limit the time span to 80 years.
In the context of Genesis 6:3, Moses wrote about the tremendous evil in the world during the time of Noah. He highlighted the sinfulness of the people in very strong terms.
Then the Lord saw that the wickedness of man was great in the earth, and that every intent of the thoughts of his heart was only evil continually. And the Lord was sorry that He had made man on the earth, and He was grieved in His heart. So the Lord said, “I will destroy man whom I have created from the face of the earth, man and beast, creeping thing and birds of the air, for I am sorry that I have made them. (Genesis 6:5–8)
The severity of the people’s sin would result in global judgment from God. Because of their depravity, God destroyed every human being and even the animals. In this context, we can see that Genesis 6:3 does not deal with the length of time a human will live. Rather, it indicates the longsuffering nature of God in the midst of His wrath. He was allowing even the most evil people of Noah’s time 120 years to repent of their sin before he would judge them with a global flood. Genesis 6:8 says, “
But Noah found grace in the eyes of the Lord.” During this time, Noah was a preacher of righteousness, and he also built an Ark for his family and himself.
In the context of Psalm 90:10, Moses pleaded for God’s mercy on human beings who live in a sin-cursed world. He reflected on the eternal attributes of God and contrasted them with the finite existence of man. Man, because of sin and disobedience, brought on himself wrath and judgment from a holy God.
For we have been consumed by Your anger, and by Your wrath we are terrified. You have set our iniquities before You, our secret sins in the light of Your countenance. (Psalm 90:7–8)
Moses informed us that the length of a man’s life averages out to between 70–80 years on earth (Psalm 90:10). Due to this time span, Moses said, “
So teach us to number our days, that we may gain a heart of wisdom” (Psalm 90:12). We are to live the remainder of our days in wisdom and holiness with the chief aim of pleasing God with our lives.
The Genesis passage deals with God’s longsuffering and the length of time He is willing to allow people to repent. The Psalm deals with finite humans who are in need of God’s mercy. Upon careful examination, we can conclude that these passages both give us important insight into the existence of human beings and the judgment that each human must face when their time on earth has concluded. Whether a human being lives to be 80 or 120, their time on earth is very brief when seen from God’s perspective.
For a thousand years in Your sight are like yesterday when it is past, and like a watch in the night. You carry them away like a flood; they are like a sleep. In the morning they are like grass which grows up: In the morning it flourishes and grows up; in the evening it is cut down and withers. (Psalm 90:4–6)
For what is your life? It is even a vapor that appears for a little time and then vanishes away. (James 4:14)
The brevity of our life should cause us to examine our spiritual condition to see whether we are prepared to spend eternity in heaven with Jesus or eternal separation from Him in hell.