From
The Didache, chapter 11.
1 Whosoever, therefore, shall come and teach you all these things aforesaid, him do ye receive;
2 but if the teacher himself turn and teach another doctrine with a view to subvert you, hearken not to him; but if he come to add to your righteousness, and the knowledge of the Lord, receive him as the Lord.
3 But concerning the apostles and prophets, thus do ye according to the doctrine of the Gospel.
4 Let every apostle who cometh unto you be received as the Lord.
5 He will remain one day, and if it be necessary, a second; but if he remain three days, he is a false prophet.
6 And let the apostle when departing take nothing but bread until he arrive at his resting-place; but if he ask for money, he is a false prophet.
7 And ye shall not tempt or dispute with any prophet who speaketh in the spirit; for every sin shall be forgiven, but this sin shall not be forgiven.
8 But not every one who speaketh in the spirit is a prophet, but he is so who hath the disposition of the Lord; by their dispositions they therefore shall be known, the false prophet and the prophet.
9 And every prophet who ordereth in the spirit that a table shall be laid, shall not eat of it himself, but if he do otherwise, he is a false prophet;
10 and every prophet who teacheth the truth, if he do not what he teacheth is a false prophet;
11 and every prophet who is approved and true, and ministering in the visible mystery of the Church, but who teacheth not others to do the things that he doth himself, shall not be judged of you, for with God lieth his judgment, for in this manner also did the ancient prophets.
12 But whoever shall say in the spirit, Give me money, or things of that kind, listen not to him; but if he tell you concerning others that are in need that ye should give unto them, let no one judge him.