Genesis 11:26 *does not* say Terah had Abraham when he was 70 years old. Genesis 11:26 states Terah had three children, with the first child born when Terah was 70. Abram is mentioned first by Moses because of his historical significance to Israel. If, as Genesis 12:4 states, Abram was 75 when Terah died at age 205 (Genesis 11:32), then Abram was born when Terah was 130 years old. Since, as is the case, Genesis does not state how old when Terah was when Abram was born but does state how old Abram and Terah were when Terah died, then Abram was not born when Terah was 70. Abram was born when Terah was 130.
Abraham first received the Abrahamic covenant while living in Ur of the Chaldees, Genesis 11:31; 12:1–3; 15:7; Joshua 24:2–3; Nehemiah 9:7; Acts 7:2–4. Terah, as being the head of the family, is mentioned as having moved the family “to go to the land of Canaan,” and stopping in Haran, Genesis 11:31. Genesis 12:1 presents the move to Canaan from Abram’s perspective: a response to God’s promise. Genesis 12:1 may assume Terah’s impending death: “Get away from . . . your father’s house.” Viewed culturally, Abram would have remained with his father until his father’s death. The family stopped in Haran, probably owing to poor health on the part of Terah, who was near the end of his life (Genesis 12:4; Acts 7:4). The most reasonable view is the extended family lived in Haran for just a few years before Terah died at age 205, Genesis 11:32. Abram continued the journey to Canaan after Terah died when he (Abram) was 75, Genesis 12:4. Acts 7:4, *does not* state Abraham was 135 when he left Haran. Genesis 12:4 states Abram was 75 when he left Haran.