TSK
Treasury of Scripture Knowledge references in KJV.
And I, behold, I have taken the Levites from among the children of Israel instead of all the firstborn that openeth the matrix among the children of Israel: therefore the Levites shall be mine;
From thirty years old and upward even until fifty years old, all that enter into the host, to do the work in the tabernacle of the congregation.
And thou shalt set the Levites before Aaron, and before his sons, and offer them [for] an offering unto the LORD.
¶ Moreover David and the captains of the host separated to the service of the sons of Asaph, and of Heman, and of Jeduthun, who should prophesy with harps, with psalteries, and with cymbals: and the number of the workmen according to their service was: