2 Chronicles 35:15

The singers, the sons of Asaph, were also at their stations according to the command of David, Asaph, Heman, and Jeduthun the king’s seer; and the gatekeepers at each gate did not have to depart from their service, because the Levites their brethren prepared for them.

1 Chronicles 9:17-19

Now the gatekeepers were Shallum and Akkub and Talmon and Ahiman and their relatives (Shallum the chief

1 Chronicles 25:1-7

Moreover, David and the commanders of the army set apart for the service some of the sons of Asaph and of Heman and of Jeduthun, who were to prophesy with lyres, harps and cymbals; and the number of those who performed their service was:

1 Chronicles 26:12-19

To these divisions of the gatekeepers, the chief men, were given duties like their relatives to minister in the house of the Lord.

1 Chronicles 16:41-42

With them were Heman and Jeduthun, and the rest who were chosen, who were designated by name, to give thanks to the Lord, because His lovingkindness is everlasting.

1 Chronicles 23:5

and 4,000 were gatekeepers, and 4,000 were praising the Lord with the instruments which David made for giving praise.

2 Chronicles 29:25-26

He then stationed the Levites in the house of the Lord with cymbals, with harps and with lyres, according to the command of David and of Gad the king’s seer, and of Nathan the prophet; for the command was from the Lord through His prophets.

Psalm 77:1

For the choir director; according to Jeduthun. A Psalm of Asaph.
My voice rises to God, and I will cry aloud;
My voice rises to God, and He will hear me.

Psalm 78:1

A Maskil of Asaph.
Listen, O my people, to my instruction;
Incline your ears to the words of my mouth.

Psalm 79:1

A Psalm of Asaph.
O God, the nations have invaded Your inheritance;
They have defiled Your holy temple;
They have laid Jerusalem in ruins.

Treasury of Scripture Knowledge

Summary

And the singers the sons of Asaph were in their place, according to the commandment of David, and Asaph, and Heman, and Jeduthun the king's seer; and the porters waited at every gate; they might not depart from their service; for their brethren the Levites prepared for them.

Bible References

The porters

1 Chronicles 9:17
Now the gatekeepers were Shallum and Akkub and Talmon and Ahiman and their relatives (Shallum the chief
1 Chronicles 26:14
The lot to the east fell to Shelemiah. Then they cast lots for his son Zechariah, a counselor with insight, and his lot came out to the north.