'Generations' in the Bible

This is the book (the written record, the history) of the generations of [the descendants of] Adam. When God created man, He made him in the likeness of God [not physical, but a spiritual personality and moral likeness].

These are the records of the generations (family history) of Noah. Noah was a righteous man [one who was just and had right standing with God], blameless in his [evil] generation; Noah walked (lived) [in habitual fellowship] with God.

And God said, “This is the token (visible symbol, memorial) of the [solemn] covenant which I am making between Me and you and every living creature that is with you, for all future generations;

These are the records of the generations (descendants) of Shem, Ham, and Japheth, the sons of Noah; and the sons born to them after the flood:

These are the families of the sons of Noah, according to their descendants, by their nations; and from these [people] the nations were separated and spread abroad on the earth after the flood.

These are the records of the generations of Shem [from whom Abraham descended]. Shem was a hundred years old when he became the father of Arpachshad, two years after the flood.

I will establish My covenant between Me and you and your descendants after you throughout their generations for an everlasting covenant, to be God to you and to your descendants after you.

Further, God said to Abraham, “As for you [your part of the agreement], you shall keep and faithfully obey [the terms of] My covenant, you and your descendants after you throughout their generations.

Every male among you who is eight days old shall be circumcised throughout your generations, [including] a servant whether born in the house or one who is purchased with [your] money from any foreigner, who is not of your descendants.