“Judah and Benjamin” are the lay people of those two tribes.
Matthew Henry
Concise Bible Commentary
All our cities, all our houses, must have holiness to the Lord written upon them. The believer should undertake nothing which he does not dedicate to the Lord. We are concerned to cleanse our hands, and purify our hearts, when any work for God is to pass through them. Those that would be employed to sanctify others, must sanctify themselves, and set themselves apart for God. To those who are sanctified, all their creature-comforts and enjoyments are made holy. The people greatly rejoiced. All that share in public mercies, ought to join in public thanksgivings.
SDA Bible Commentary (limited)
Volume 1-7
34. Judah, and Benjamin. Certain lay people belonging to these tribes seem to be meant.
Shemaiah, and Jeremiah. Representatives of two more priestly families (see chs.10:2, 8; 12:1, 6).