Abraham, whose father was Thara, was born in the one thousand and seventeenth year after the deluge. His wife was called Sara, and his dwelling-place was at first in the country of the Chaldæans. He then dwelt along with his father at Charræ. Being at this time spoken to by God, he left his country and his father, and taking with him Lot, the son of his brother, he came into the country of the Canaanites, and settled at a place named Sychem. Ere long, owing to the want of grain, he went into Egypt, and again returned.
Lot, owing to the size of the household, parted from his uncle, that he might take advantage of more spacious territories in what was then a vacant region, and settled at Sodom. That town was infamous on account of its inhabitants, males forcing themselves upon males, and it is said on that account to have been hateful to God. At that period the kings of the neighboring peoples were in arms, though previously there had been no war among mankind. But the kings of Sodom and Gomorrha and of the adjacent territories went forth to battle against those who were making war upon the regions round about, and being routed at the first onset, yielded the victory to the opposite side.
Then Sodom was plundered and made a spoil of by the victorious enemy, while Lot was led into captivity. When Abraham heard of this, he speedily armed his servants, to the number of three hundred and eighteen, and, stripping of their spoils and arms the kings flushed with victory, he put them to flight. Then he was blessed by Melchisedech the priest, and gave him tithes of the spoil. He restored the remainder to those from whom it had been taken.
Source: Sacred History (New Advent)