Why Abraham was not born when Terah was 70

correct synchronism (Ussher):

            Jewish chronologies, and many others make the fatal error of assuming that Abraham was born when Terah was 70 years old.   To show the hazardous nature of this assumption consider the following.

            1. Noah is said to have begotten, "Shem, Ham, and Japheth" when he was 500 (Gen. 5:32).

            2. The flood was in Noah's 600th year (Gen. 7:11).

            3.  Shem was 100 years old 2 years after the flood (Gen. 11:10).

            This means that Shem was 98 in the year of the flood and born when Noah was 502.

            4.  Ham was the youngest son of Noah (Gen. 9:22, 24).  Ham told his brothers, when he should have shut up and covered his father without telling anyone.  Noah could not bring himself to curse Ham, so he cursed his grandson Canaan, and blessed Shem and Japheth.

            These facts show that the order of birth was, 1. Japheth, 2. Shem, 3. Ham.   Only Japheth was born when Noah was 500.   Shem was born at 502, and Ham when Noah was 503 or later.   Evidently, when the Scripture says "X, Y, and Z were begotten at age A" we cannot assume that X was begotten at age A.

            The Scripture says:

            KJV Genesis 11:26 And Terah lived seventy years, and begat Abram, Nahor, and Haran.

            We need more information, because Abram is only listed first because he is the heir like Shem.  Nahor is the second most important, and Haran the least.   But Haran was most likely the oldest and the one born when Terah was 70, because he died in Ur of the Chaldees (Gen. 11:27-28).  Haran was also the father of Abraham's Nephew, Lot, who were contemporaries.   Nahor married the daughter of Haran and Abraham another daughter of Terah, but by a different wife.

            The missing information is supplied in two passages:

             KJV Genesis 11:32 And the days of Terah were two hundred and five years: and Terah died in Haran.

            KJV Genesis 12:4 So Abram departed, as the LORD had spoken unto him; and Lot went with him: and Abram was seventy and five years old when he departed out of Haran.

             And it is confirmed by one more:

            KJV Acts 7:4 Then came he out of the land of the Chaldaeans, and dwelt in Charran: and from thence, when his father was dead, he removed him into this land, wherein ye now dwell.