Thematic Bible: What preachers should do

Know ye not that they that minister about sacred things eat of the things of the temple, and they that wait upon the altar have their portion with the altar? Even so did the Lord ordain that they that proclaim the gospel should live of the gospel.

My little children, these things write I unto you that ye may not sin. And if any man sin, we have an Advocate with the Father, Jesus Christ the righteous: and he is the propitiation for our sins; and not for ours only, but also for the whole world. And hereby we know that we know him, if we keep his commandments. read more.
He that saith, I know him, and keepeth not his commandments, is a liar, and the truth is not in him; but whoso keepeth his word, in him verily hath the love of God been perfected. Hereby we know that we are in him: he that saith he abideth in him ought himself also to walk even as he walked.