Genesis 21:30

And he said, For these seven ewe lambs shalt thou take of my hand, that they may be a witness unto me that I have digged this well. This was a special transaction with reference to the well which the servants of Abimelech had taken from Abraham. Abimelech's surprised question as to the meaning of this action received the answer that the king was to take them from the hand of Abraham for a witness to the latter that he had caused this well to be dug. Not to redeem the well, therefore, but to secure his property against any possible claims in the future Abraham set the seven ewe lambs aside.