Thematic Bible: What preachers should do

Do ye not know that those who work with sacred things live of the things of the sanctuary? and those who serve at the altar partake of the altar? Even so the Lord has ordained that those who preach the gospel should live of the gospel.

My little children, I write these things unto you, that ye sin not; and if anyone has sinned, we have an Advocate before the Father, Jesus, the righteous Christ; and he is the reconciliation for our sins, and not for ours only, but also for the sins of the whole world. And in this we do know that we have known him if we keep his commandments. read more.
He that says, I have known him, and does not keep his commandments, is a liar, and the truth is not in him. But whosoever keeps his word, in him verily is the charity of God perfected: hereby know we that we are in him. He that says he abides in him ought himself also so to walk, even as he walked.