Matthew Poole and continuators on Ezekiel 46:12

12 Now when the prince shall prepare a voluntary burnt-offering or peace-offerings voluntarily unto the LORD, one shall then open him the gate that looketh toward the east, and he shall prepare his burnt offering and his peace-offerings as he did on the sabbath-day: then he shall go forth; and after his going forth, one shall shut the gate.

One of the priest porters, as the gate was opened for this service onely on such a day, so the service performed, some priests porter shall shut it, for it must not stand open on ordinary dayes.

In the 2, 4, 5, 6, 7. verses orders were given about those offerings, which were required, which the Prince must offer, in this, direction is given about those, that are Free-will-offerings, which in all points, must be prepared, as the other were on the Sabbath-day, which see in the forementioned verses.