Genesis 26:28-31

28They answered, “We saw clearly that the Lord was with you; so we said, ‘There ought to be a sworn agreement between us’—between us and you. Let us make a treaty with you 29that you will do us no harm, just as we did not harm you but always treated you well and sent you away peacefully. And now you are blessed by the Lord.” 30Isaac then made a feast for them, and they ate and drank. 31Early the next morning the men swore an oath to each other. Then Isaac sent them on their way, and they went away peacefully.