Genesis 11:24

And Nahor lived nine and twenty years, and begat Terah:

Nahor belongs to the post-Flood genealogy, coming after the exceptionally long-lived patriarchs from Adam to Noah. He was twenty-nine years old when Terah was born. Only his age at Terah's birth is given, without stating how long he lived.

This record belongs to the evidence that human longevity declined after the Flood. Across nine generations before the Flood the average lifespan was 912 years, compared with 332 years across the nine generations after the Flood recorded in Genesis 11.

The genealogy from Shem to Abraham preserves overlapping lifetimes from Adam to Jacob, so that what God taught Adam could be told directly from person to person. Adam was still alive when Methuselah was 243 years old, and Methuselah was still alive when Shem the son of Noah was 98 years old. Shem lived 150 years after the birth of Abraham and 50 years after the birth of Isaac. Abraham lived until Jacob and Esau were 15 years old, and Isaac lived until they were 120. In this way knowledge passed from Adam to Methuselah to Shem to Abraham and Isaac to Jacob, the father of the tribes of Israel.