Shebah. i.e., an oath. therefore.

Genesis 21:31 Why he called that place Beersheba; because there they swore both of them.

Beer-sheba. i.e., the well of the oath.

Genesis 26:28 And they said, We saw certainly that the LORD was with you: and we said, Let there be now an oath between us, even between us and you...

This may have been the same city which was called Beer-sheba a hundred years before this, in the time of Abraham; but as the well, from which it had its name originally, was closed up by the Philistines, the name of the place might have been abolished with the well; when, therefore, Isaac re-opened it, he restored the ancient name of the place.