2 Chronicles 31:18

And to the genealogy of all their little ones, their wives, and their sons, and their daughters, through all the congregation: for in their set office they sanctified themselves in holiness:

For in their set office they sanctified themselves. This is the reason assigned for providing for the wives and children out of the revenues of the sanctuary-that priests, withdrawing from those secular pursuits by which they might have maintained their households, devoted themselves entirely to the functions of the ministry.