The answer to the question Jesus poses here is obvious. Of course, the owner will not invite his slave (the best translation of the Greek word doulos), after he finished his work on the land, to his table. He will surely not do that. The social relationships then did not allow for this.
7 “Will any one of you who has a servant plowing or keeping sheep say to him when he has come in from the field, ‘Come at once and recline at table’?