“the judges.” The Hebrew is elohim, which can be God, a representative or representatives of God such as judges, or even pagan gods. In this case, the logical choice seems to be the local judges, because although during the period of the wilderness wanderings it would be easy for someone to go to the Tent of Meeting where God was, this regulation was also intended to be in force once Israel got settled in the Promised Land when it would not be convenient for a slave and master to travel to Jerusalem for this ceremony. Also, although the “door” or “doorpost” is not specifically indicated here, the most logical choice is that it is the door or doorpost of the master’s house because the slave was asking to be connected to the master’s household forever.
“and he will serve him forever.” The word “forever” in this case means for a long time, because the servitude ended in the year of the Jubilee (Lev. 25:39-41).