What does Genesis 14:20 mean?

Abram is returning from defeating the four kings of the east, in order to rescue his nephew Lot and all of Lot's possessions. In doing so, Abram has also recovered the plunder taken by the enemy, including all that was taken from Sodom. Bera, the king of Sodom (Genesis 14:2), has come out to meet Abram, as has the king of Salem: a mysterious figure called Melchizedek. Here, King Melchizedek, priest of the Most High God, continues his blessing for conquering Abram begun in the previous verse.

The blessing given states clearly that the Lord was responsible for this victory, something Abram was clearly already aware of. Abram responds by tithing on the plunder he has recovered from the four kings of the east. He gives ten percent of all of it to this priest of God, Melchizedek. This may have been a customary response to a blessing at this time, but it certainly would not have been required of Abram. As the victor, the spoils of war would likely have been his to claim. He chose not to keep them.

This act of tithing will also serve as an example to Israel and God's people in the future. Tithing to the priests will become required by God's Law (see Numbers 18; Leviticus 27:30-33).