Did Abraham leave Haran before or after his father Terah died?

The difficulty rests on one assumption: that Abram was born when Terah was seventy. Genesis 11:26 does not say that. It uses the same formula as Genesis 5:32: “Noah was five hundred years old: and Noah begat Shem, Ham, and Japheth.” Those three were not born in one year. Shem was a hundred “two years after the flood”, which began in Noah’s six hundredth year (Genesis 7:6; 11:10), and Ham, named second, is called Noah’s “younger son” (Genesis 9:24). The formula gives the father’s age when his sons began to be born, and the list puts the most important son first. Abram heads Terah’s list because the story is about him, just as Isaac is named before his elder brother Ishmael at Abraham’s burial (Genesis 25:9).

If Terah was 130 when Abram was born, everything fits. Abram was seventy-five when he left Haran (Genesis 12:4); Terah had then just died, aged 205 (Genesis 11:32), as Stephen says; and Abram was eighty-six when Ishmael was born (Genesis 16:16). Genesis even hints that Haran, not Abram, was the eldest: he died first, in Ur, and his daughter Milcah married her uncle Nahor (Genesis 11:28–29). Stephen was not alone in reading Genesis this way: the first-century Jewish writer Philo also says that Abraham moved on from Haran after his father died there.

Terah lived on after Abram left

Augustine, and later Keil and Delitzsch, took Terah to be seventy at Abram’s birth, so that Terah lived sixty years after Abram left Haran. Augustine read Stephen’s words as dating Abraham’s settling in Canaan, not the day he left Haran, to after Terah’s death. Keil thought Stephen followed the order in which Genesis tells the story, since it records Terah’s death before Abram’s departure. Jewish tradition, recorded by Rashi, held the same chronology.

The Samaritan reading

The Samaritan Pentateuch gives Terah’s age at death as 145, which would mean he died in the year Abram left. The Hebrew text, the Septuagint and the other ancient versions all read 205, so the Samaritan figure may be an early attempt to remove the difficulty.

Genesis never says in what order Terah’s sons were born, so the answer above is an inference, though a well-grounded one. Some find it odd that Abraham thought fathering a son at a hundred so remarkable (Genesis 17:17) if Terah had fathered him at 130. But Abraham’s wonder was as much about Sarah, who was ninety and long past childbearing (Genesis 18:11), and life spans were shortening quickly in those generations.