John Gill Commentary 1 Chronicles 9:13

"and their brethren, heads of their fathers` houses, a thousand and seven hundred and threescore; very able men for the work of the service of the house of God." — 1 Chronicles 9:13 (ASV)

And their brethren, heads of the house of their fathers, one thousand and seven hundred and threescore . ] These, with other priests, made up this number, which was greater than those of Judah and Benjamin, that dwelt in Jerusalem, put together:

very able men for the work of the service of the house of God : men that had not only strength of body, which some part of the work of the priests required; but had courage and fortitude of mind to set about the service of God with cheerfulness, and to preserve it from corruption.