After his return from the defeat of Chedorlaomer and the kings who were with him, the king of Sodom went out to meet him at the Valley of Shaveh (that is, the King’s Valley). And Melchizedek king of Salem brought out bread and wine. (He was priest of God Most High.) And he blessed him and said,

“Blessed be Abram by God Most High,

Possessor of heaven and earth;

and blessed be God Most High,

who has delivered your enemies into your hand!”

And Abram gave him a tenth of everything. And the king of Sodom said to Abram, “Give me the persons, but take the goods for yourself.” But Abram said to the king of Sodom, “I have lifted my hand to the LORD, God Most High, Possessor of heaven and earth, that I would not take a thread or a sandal strap or anything that is yours, lest you should say, ‘I have made Abram rich.’ I will take nothing but what the young men have eaten, and the share of the men who went with me. Let Aner, Eshcol, and Mamre take their share.” 

Genesis 14:17–24 (ESV)