The story of the destruction of Sodom and Gomorrah shows God’s mercy at its finest. After he threatens to destroy the cities, Lot, who resides in one of them, bargains with his god, finally convincing him to spare the cities if Lot can find five righteous men in them (apparently, righteous women aren’t good enough).
The bar is not set high: Lot himself is considered righteous, although he clearly suffers from the sin of pride (it takes a pretty big ego to bargain with god as an equal). However, he does have one virtue that god appreciates, that of shameless toadying. Indeed, Lot is so desperate to curry favour with god and his servants that he offers his virgin daughters to the baying mob to do with as they please if they will simply consent to leave god’s servants alone.
For this, god spares Lot and his daughters, allowing them to flee the city before he smites down upon it with great vengeance and furious anger – although Lot’s wife, whose only crime is to like watching explosions, is turned into a pillar of salt as a punishment – which is pretty harsh considering how few fans of action movies have ever been similarly afflicted.