Genesis 12:1 is the only call by God to Abraham noted in scripture. Genesis 11:31 tells us that Ter'ah took Abraham, Lot, and Sarai, and began the journey to Canaan, perhaps out of grief for the loss of his son Haran, but certainly before the call on Abraham. Acts
Genesis 11:31
Terah took his son Abram, his grandson Lot son of Haran, and his daughter-in-law Sarai, the wife of his son Abram, and together they set out from Ur of the Chaldeans to go to Canaan. But when they came to Harran, they settled there.(NIV)
Acts 7:2-4 supports this single call theory.Vs2b "The God of glory appeared unto our father Abraham when he was in Mesopotamia before he dwelt in Charran.:
Acts 7:2b
The God of glory appeared unto our father Abraham when he was in Mesopotamia before he dwelt in Charran.(NIV)
The beginning of Genesis 12:1 indicate that the call had already been given and the response was only now being recorded. Furthermore even though the call was to Abraham, God had stirred the heart of Terah to begin the journey to the very place he promised to Abraham so that when Terah died Abraham continued in God's divine will.