Genesis 14:24

save only that which the young men have eaten, and the portion of the men which went with me, Aner, Eshcol, and Mamre; let them take their portion. It is a kind, but solemn and emphatic refusal. With a confession in the true God, in whose name he swears, Abram declares that the men belonging to his allies may take advantage of the offer and claim their share of the spoils, and he would be willing to accept what his servants had consumed in food daring their campaign; but as for himself, not even a thread or a sandal-strap would he accept from the king of Sodom, lest the latter might afterward boast that Abram owed his riches to him. Abram wanted to be under no obligations to the heathen king. Even so the believers today are encouraged to do good also to the unbelievers; but beyond that they should not go, lest their Christianity be endangered.