‘And Abraham reproved Abimelech because of the well of water which Abimelech's servants had violently taken away.'
The well, clearly fed by a powerful spring, must have been of great importance for it to come up at this point, which was why both groups wanted it. Indeed regular supplies of water were always important in all periods, but this must have been exceptional. That is why Abraham wants it brought within any covenant. It was so important that it in fact became the centre of their operations.
Digging a well satisfactorily could be a difficult and time consuming task, and when it was completed and the well producing satisfactorily it gave great satisfaction. It was not a happy thing therefore that it had then been snatched from them by force.
The incident does indicate that all was not necessarily well between the two groups. Presumably Abraham has not retaliated because he has considered the effect on the relationship between the two groups, or it may be that it was very recent and he was still considering what to do, but it clearly rankled. Now the opportunity had come to solve the matter.