Abram.

Genesis 11:27-32
Now these are the generations of Terah: Terah begat Abram, Nahor, and Haran; and Haran begat Lot…

Genesis 17:5
Neither shall thy name any more be called Abram, but thy name shall be Abraham; for a father of many nations have I made thee.

Joshua 24:2
And Joshua said unto all the people, Thus saith the LORD God of Israel, Your fathers dwelt on the other side of the flood in old time, even Terah, the father of Abraham, and the father of Nachor: and they served other gods.