Many theologians and such throughout the years have interpreted Gen 6:3 to mean that humans only have 120 years to live, however, many post-flood people lived way longer than that, Terah: 205 (Gen 11:32), Abraham: 175 years (Gen 25:7), and Isaac: 180 years (Gen 35:28). What does this mean?
Gen 6:3 (NLT) Then the Lord said, “My Spirit will not put up with humans for such a long time, for they are only mortal flesh. In the future, their normal lifespan will be no more than 120 years.”
Gen 6:3 (KJV) And the Lord said, My spirit shall not always strive with man, for that he also is flesh: yet his days shall be an hundred and twenty years.
There is another possible interpretation of the 120-year limit mentioned in Genesis 6:3. In Genesis 6:3, God states, “My spirit shall not always strive with man, for that he also is flesh: yet his days shall be an hundred and twenty years.” According to the Dead Sea Scrolls and Targum Jonathan’s (2nd Century BC) commentary on Genesis 6:3, God is said to have spoken this when Noah was 480 years old. 120 years later, Noah was 600, and it was then that God sent the flood.
“In the year four hundred and eighty of Noah’s life, Noah reached the end of them. And God said: ‘My Spirit will not reside in man forever. Their days shall be fixed at one hundred and twenty years until the end of the waters of the flood.” – [4Q252 1.1-3, see Devorah Dimant, “The Flood as Preamble: The Perspective of the Qumran Hebrew Texts,” pp. 110-122]
“And the Lord said by His Word, All the generations of the wicked which are to arise shall not be purged after the order of the judgments of the generation of the deluge, which shall be destroyed and exterminated from the midst of the world. Have I not imparted My Holy Spirit to them, (or, placed My Holy Spirit in them,) that they may work good works? And, behold, their works are wicked. Behold, I will give them a prolongment of a hundred and twenty years, that they may work repentance, and not perish.” [Targum Jonathan’s commentary on Genesis 6:3]
If Gen 6:3 were spoken by God when Noah was 480 years old, that would mean it was at least a countdown before the flood came and wiped out all flesh that could not survive in water for at least a year. There is a hypothesis that when it says, “he also is flesh”, the also implies that this verse is not about humans but about the offspring of the sons of God and the daughters of mankind. He suggests that is why the text says “he ALSO is flesh”. This suggests a new kind of flesh that is separate and distinct from humanity, as indicated by the use of the word “also”. That suggests that this is about the Sons of God and not humans because they are the new kind of flesh that “also” existed alongside humans, and they would be killed along with humans, and that is why they are mentioned in the next verse.
Gen 6:4 (NLT) In those days, and for some time after, giant Nephilites lived on the earth, for whenever the sons of God had intercourse with women, they gave birth to children who became the heroes and famous warriors of ancient times.
New giants emerged after the flood in the Canaan land. It is unknown whether this is because the flood was local and they, along with other people, survived, or if new Giants were created after the flood. In the case of a global flood, new heavenly beings could have mated with humans, or their genes could have been carried by women and passed on by Noah’s daughters-in-law.
Either way, the point is that the Dead Sea Scroll offers a different perspective from first-century Jews on the understanding of Genesis 6:3, which addresses the fact that patriarchs after Noah, including Job, lived significantly longer than 120 years. Even patriarchs just before Moses lived past 120 years. According to Exodus 6:16-20, Moses’ father, Amram, lived until 137, Kohath, his grandfather, until 133, and Levi, his great-grandfather, lived until 137. Moses is the first person recorded to have died at 120. Moses’ brother Aaron died the same year as Moses, at the age of 123.
The mainstream theory is based on the assumption that God intended 120 years to be a goal achieved gradually over time, until the time of Moses, as the ages of the patriarchs decrease from Noah to Moses. Moses is the last biblical figure mentioned (excluding Job) who lived that long. The Dead Sea Scrolls, which date back to around the 4th century BC, weren’t discovered until 1948. Therefore, the KJV authors and other European church fathers throughout the ages may not have had access to this view or may have rejected it. Long story short, there are two interpretations, so pick whichever one you believe is correct until God reveals more info. The one held by the Jews of the first century is likely what Jesus and the New Testament authors believed.
Source Reference:
4Q252 1.1-3, see Devorah Dimant, “The Flood as Preamble: The Perspective of the Qumran Hebrew Texts,” pp. 110-122
Targum Jonathan’s commentary on Genesis 6:3