Bamidbar 4:22-24

Orthodox Jewish Bible

²² Take also the census of the Bnei Gershon, throughout the bais avot of them, by their mishpekhot;

²³ From shloshim shanah (thirty years old) and upward until chamishim shanah (fifty years old) shalt thou number them; all that enter to serve the tz’va (holy militia service of Hashem), to labor in the Avodah in the Ohel Mo’ed.

²⁴ This is the Avodat Mishpekhot Gershoni, as relates to service and massa (burden):