John Wesley on 1 Chronicles 9:18

King's gate - In the east - gate of the temple, which was so called, because the kings of Judah used to go to the temple through that gate. Under this gate he comprehends all the rest, which also were guarded by these porters. Companies - Or, according to the courses. They kept the gates successively, according to that method into which the Levites were distributed, for the more convenient management of their several offices; among which this of the porters was one.