John Gill Commentary 1 Chronicles 29:6

"Then the princes of the fathers` [houses], and the princes of the tribes of Israel, and the captains of thousands and of hundreds, with the rulers over the king`s work, offered willingly;" — 1 Chronicles 29:6 (ASV)

Then the chief of the fathers and princes of the tribes of
Israel
The princes of the twelve tribes:

and the captains of thousands, and of hundreds, with the rulers over
the king's work ;
who were now assembled, (1 Chronicles 28:1)

offered willingly ;
and cheerfully; needed no more arguments to press them to it, but at once readily communicated.