Two stories Esau/Jacob, Abimelech/Isaac: Genesis 25–28
As Isaac grew richer (the Lord did, indeed, bless him), a dispute over water rights broke out: Isaac reopened wells his father had dug, and the Philistines filled them in again. Abimelech was forced to move Isaac on. As Isaac moved around, his servants dug more wells, the Philistines claimed them for themselves, and Isaac moved on without a fuss.
Isaac eventually settled once he managed to dig a well (at Rehoboth) that the Philistines weren’t interested in. It was only 30 kilometres from Beersheba, the very place where Abraham and Abimelech had come to an agreement over who dug a well some decades earlier. Isaac moved there and Abimelech came over very quickly to make a treaty:
26:28-29 We can plainly see that the Lord is with you. So we want to enter into a sworn treaty with you. Let’s make a covenant. Swear that you will not harm us, just as we have never troubled you. We have always treated you well, and we sent you away from us in peace. And now look how the Lord has blessed you!
Amazingly, Isaac’s servants found more water just after the treaty was made and Abimelech left. This well was called Shibah (which means ‘oath’), and the town there was called Beersheba (‘well of the oath’). This confirmed the name that Abraham gave it in Genesis 21. It could well be a case of Isaac’s servants knowing exactly where to dig—some of them could have been children of Abraham’s servants who saw the first treaty at Beersheba.
Stealing wells, or filling them in, was no small thing. They were crucial and would have been hard work to dig in the first place. One well at Beersheba (known as Abraham’s well) is now three-metres wide and 26-metres deep.
It must have been frustrating for Isaac to have to keep digging and moving, then digging again and moving again. But it could be that Isaac didn’t have the military power to take on even the Philistine shepherds (who knows what they had as backup). Abimelech obviously feared God: Sodom and Gomorrah would have still been in living memory, and Abimelech had experienced God first-hand when he mistakenly tried to take Sarah as a wife. It is not impossible that Isaac’s approach was to end up at Beersheba and see what Abimelech would do about his oath with Abraham then.