In context
27So Abraham took sheep and cattle and gave them to Abimelech, and the two of them made a covenant. 28Abraham set apart seven ewe lambs from the flock. 29Abimelech asked Abraham, “What are these seven ewe lambs you have set apart?” 30He said, “Accept these seven ewe lambs from my hand, that they may be a witness for me that I dug this well.” 31That is why that place was called Beersheba — because there the two of them swore an oath.
