1 Chronicles 16:37

So he left Asaph and his brothers there before the ark of the covenant of Yahweh to minister before the ark regularly {as each day required},

2 Chronicles 8:14

And in accord with the ordinance of David his father he appointed working groups of priests for their service, Levites for their responsibilities for praise and cultic service before the priests {according to the daily requirement}, and the gatekeepers in their working groups, gate by gate. For thus David the man of God had commanded.

Ezra 3:4

And they kept the feast of booths, as it is written, and [offered] burnt offerings day by day in number according to the ordinance {as described for each day}.

1 Chronicles 15:17-24

So the Levites appointed Heman son of Joel, and from his brothers, Asaph the son of Berekiah, and from the sons of Merari, their brothers, Ethan the son of Kushaiah;

1 Chronicles 16:4-6

Then he appointed some of the Levites as ministers before the ark of Yahweh, to invoke, thank, and praise Yahweh the God of Israel.

1 Chronicles 25:1-6

And David and the commanders of the army set apart for the service the sons of Asaph, [of] Heman, and [of] Jeduthun, who prophesied with stringed instruments, with harps, and with cymbals. And their inventory of the men of the work [and] for their duty was:

Treasury of Scripture Knowledge

Summary

So he left there before the ark of the covenant of the LORD Asaph and his brethren, to minister before the ark continually, as every day's work required:

Bible References

Before the ark

1 Chronicles 16:4
Then he appointed some of the Levites as ministers before the ark of Yahweh, to invoke, thank, and praise Yahweh the God of Israel.
1 Chronicles 15:17
So the Levites appointed Heman son of Joel, and from his brothers, Asaph the son of Berekiah, and from the sons of Merari, their brothers, Ethan the son of Kushaiah;
1 Chronicles 25:1
And David and the commanders of the army set apart for the service the sons of Asaph, [of] Heman, and [of] Jeduthun, who prophesied with stringed instruments, with harps, and with cymbals. And their inventory of the men of the work [and] for their duty was:

As every

2 Chronicles 8:14
And in accord with the ordinance of David his father he appointed working groups of priests for their service, Levites for their responsibilities for praise and cultic service before the priests {according to the daily requirement}, and the gatekeepers in their working groups, gate by gate. For thus David the man of God had commanded.
Ezra 3:4
And they kept the feast of booths, as it is written, and [offered] burnt offerings day by day in number according to the ordinance {as described for each day}.