'Ewe lambs' in the Bible

Then Abraham set [off] seven ewe-lambs of the flock by themselves.

And Abimelech said to Abraham, "What [is the meaning of] these seven ewe-lambs that you have set [off] by themselves?"

And he said, "You shall take the seven ewe-lambs from my hand {as proof on my behalf} that I dug this well."