The gatekeepers were on the four sides, east, west, north, and south. And their kinsmen who were in their villages were obligated to come in every seven days, in turn, to be with these, for the four chief gatekeepers, who were Levites, were entrusted to be over the chambers and the treasures of the house of God. And they lodged around the house of God, for on them lay the duty of watching, and they had charge of opening it every morning.
1 Chronicles 9:24-27
When David brought the ark of God and the tabernacle to Jerusalem, one of the main tasks became organizing the public expressions of worship in God's house. Jerusalem was big, cosmopolitan, and central to the nation's life. The ark had been in an out of the way countryside setting in Shiloh for generations. Now it was front and center in national life. That meant that more people would worship at the tabernacle now that it was located in the capital city.
Under David's leadership, the Levites appointed singers and musicians, as well as gatekeepers and guards. The worship complex in Jerusalm grew as it housed treasuries where offerings were stored and living quarters for various worship personnel. And this necessitated more staffing in order to distribute gifts and to guard them. A new class of administrative duties was created and organized around the worship of Yahweh and the offering of sacrifices in Jerusalem.
What was it like to be a gatekeeper? They rose early in the morning to open the house of God for worship. First with the tabernacle and then later in the temple, four gates (one in each cardinal direction) were to be opened. Guards were posted 24/7 and as the gatekeepers arrived, the guards would report and prepare for the day's worship activities and incoming worshipers and pilgrims. This happened every day, including the Sabbath, for priestly duties were always needed. God was always worshiped in His house and the gatekeepers kept that worship always available to God's people.
On of these worship workers, Korah, captured the anticipation of worship each morning at the gates:
For a day in your courts is better
than a thousand elsewhere.
I would rather be a doorkeeper in the house of my God
than dwell in the tents of wickedness.
And since one day with God in worship is better than a thousand days without Him, a gatekeeper at God's house opened the doors to a thousand great joys!