This Bible contradiction is from the Skeptic's Annotated Bible.

Verses

God called Abraham before he moved to Haran.

Acts 7:2-3 View context

And he said, Men, brethren, and fathers, hearken; The God of glory appeared unto our father Abraham, when he was in Mesopotamia, before he dwelt in Charran,

And said unto him, Get thee out of thy country, and from thy kindred, and come into the land which I shall shew thee.

God called Abraham after he moved to Haran

Genesis 11:31- 12:4 View context

And Terah took Abram his son, and Lot the son of Haran his son's son, and Sarai his daughter in law, his son Abram's wife; and they went forth with them from Ur of the Chaldees, to go into the land of Canaan; and they came unto Haran, and dwelt there.