Did God promise mankind a hundred and twenty years to live?

The idea that God promised mankind a lifespan of 120 years comes from Genesis 6:3, where it states, "My Spirit shall not strive with man forever, for he is indeed flesh; yet his days shall be one hundred and twenty years." This verse is often interpreted as indicating a limit to human lifespan following the pre-Flood era. However, it is debated among scholars whether this was a specific promise or a general statement about the declining longevity of humanity.