So it came about, when God destroyed the cities of the surrounding area, that God remembered Abraham, and sent Lot out of the midst of the destruction, when He overthrew the cities in which Lot had lived.
Genesis 19:29 (NASB)So Abram went away as the Lord had spoken to him; and Lot went with him. Now Abram was seventy-five years old when he departed from Haran.
Genesis 12:4 (NASB)
The rabbis connect Genesis 19:29 to Genesis 12:4, and suggest that Lot was not just spared from the destruction of Sodom, but from the destruction of Haran as well.
Both cases are because of Abraham.