Rehoboth means an end has come to fruitless labour. For a man who has been labouring and not getting results, at Rehoboth end comes to such labour and he begins to experience fruitfulness in the land.
Before Isaac got to his Rehoboth, he had dug two wells but could not settle down because the people fought over them. It must have been a discouraging series for him. He was working and other men were claiming it until God brought him to the place of rest.