Background: The Southern Opening
"This gate shall be shut"
These are the two keys to the great gate of the Sanctuary. However, they do not open the Sanctuary gates themselves. On either side of these doors, there were two small openings, similar to the openings which led from the Place of the Fire into the Court (see "The Dawn Patrol," page 7); one from the north (on the right-hand side of the gates) and one from the south (on the left). The southern opening was never opened, and no man ever passed through it. It was concerning this entrance that Ezekiel prophesied (Ez. 44:2), "And the L-rd said to me, this gate shall be shut, it shall not be opened and no man shall enter in by it, because the L-rd, the G-d of Israel, has entered in by it, therefore it shall be shut." This gate was to remain closed in order to show that not every doorway is needed solely for the purpose of the entrance and exit of men; the Holy One needs no gate to be opened for Him. This one remained closed, but yet the Shechina, the Divine Presence rested within.
These were the keys to the entrance on the north side of the gate. The Sanctuary gates were locked from the inside, and therefore it was necessary to go through these smaller doors and around to the gates from within. The Levite who has been appointed to open the Sanctuary takes these keys from the priests and, opening the small door to the right, enters first into an antechamber and then into the area of the Sanctuary itself. Reaching the great gates, he removes the door-bolt and the locks and opens wide the gates.