1 Corinthians 9:13-14

Know you not that those who perform sacred rites eat from the temple? Those who wait on the altar partake of the altar?

Galatians 6:6

Let him that is taught the word communicate with him that teaches of all good things.

Hebrews 7:5

And the sons of Levi who receive the priesthood, have a commandment to tithe the people according to the law, that is their brothers, although descended from 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
Know you not that those who perform sacred rites eat from the temple? Those who wait on the altar partake of the altar?
Galatians 6:6
Let him that is taught the word communicate with him that teaches of all good things.