He shall go in by the porch of that gate To go in at the eastern gate was the privilege of the prince and the priests only; the people were to enter in by the north or south gates, as is mentioned in the following verse. He that entereth in by the way of the north gate, shall go out by the way of the south, &c. These words imply the reason why the people were not to come in at the east gate, because, there being no passage or thoroughfare out of the temple westward, if they had entered in at the east gate, they must have returned back the same way they came in, which would have occasioned a vast throng and hinderance, considering the multitude that came to the temple. And perhaps this order was also designed to take away any superstitious distinction between the several gates of the temple, by commanding that every one should go out the opposite way to that by which he came in, whether it were toward the north or south. And the prince in the midst of them The prince shall pay the same attendance upon God's worship with the people, since all men are equal in the sight of God.
Ezekiel 46:8-10
8 And when the prince shall enter, he shall go in by the way of the porch of that gate, and he shall go forth by the way thereof.
9 But when the people of the land shall come before the LORD in the solemn feasts, he that entereth in by the way of the north gate to worship shall go out by the way of the south gate; and he that entereth by the way of the south gate shall go forth by the way of the north gate: he shall not return by the way of the gate whereby he came in, but shall go forth over against it.
10 And the prince in the midst of them, when they go in, shall go in; and when they go forth, shall go forth.