NET
4 This is what you must do. One-third of you priests and Levites who are on duty during the Sabbath will guard the doors.
Darby
4 This is the thing which ye shall do: a third part of you that come in on the sabbath, of the priests and of the Levites, shall be keepers of the doors;
KJV
4 This [is] the thing that ye shall do; A third part of you entering on the sabbath, of the priests and of the Levites, [shall be] porters of the doors;