Thematic Bible: What preachers should do

Do you not know that those performing the holy services eat the things from the temple, [and] those attending to the altar have a share with the altar? In the [same] way also the Lord ordered those who proclaim the gospel to live from the gospel.

My little children, I am writing these [things] to you in order that you may not sin. And if anyone sins, we have an advocate with the Father, Jesus Christ the righteous [one], and he is the propitiation for our sins, and not for ours only, but also for [the sins of] the whole world. And by this we know that we have come to know him, if we keep his commandments. read more.
The one who says "I have come to know him," and does not keep his commandments is a liar, and the truth is not in this person. But whoever keeps his word, truly in this person the love of God has been perfected. By this we know that we are in him. The one who says [that he] resides in him ought also to walk just as that one walked.