1 Corinthians 9:13-14

Do you not know that those who are engaged about sacred rites have their living from the temple? and that those who attend upon the altar are partakers with the altar?

Galatians 6:6

Let him that is instructed in the word share with his instructor in all good things.

Hebrews 7:5

And those of the sons of Levi, who receive the office of priesthood, have a commandment to take tithes of the people according to the law, that is, of their brethren, though they come out of the loins of Abraham:

Treasury of Scripture Knowledge

Summary

And, behold, I have given the children of Levi all the tenth in Israel for an inheritance, for their service which they serve, even the service of the tabernacle of the congregation.

Bible References

Even the service

1 Corinthians 9:13
Do you not know that those who are engaged about sacred rites have their living from the temple? and that those who attend upon the altar are partakers with the altar?
Galatians 6:6
Let him that is instructed in the word share with his instructor in all good things.