1 Chronicles 9:22-25

All these which were chosen to be porters in the gates were two hundred and twelve. These were reckoned by their genealogy in their villages, whom David and Samuel the seer did ordain in their set office. So they and their children had the oversight of the gates of the house of the LORD, namely, the house of the tabernacle, by wards. In four quarters were the porters, toward the east, west, north, and south. And their brethren, which were in their villages, were to come after seven days from time to time with them.