Genesis records that Terah took his son Abram, his grandson Lot, and Sarai from Ur of the Chaldeans intending to travel toward Canaan. They reached Harran and settled there.
After Terah's death, God called Abram to leave his country and kindred and journey to the land that God would show him.
Genesis 15 records God identifying Himself to Abram as the Lord who brought him out of Ur of the Chaldeans to give him the land of Canaan.
Nehemiah later recalls the same tradition while recounting God's covenant faithfulness to Abraham.