The Didache, Didache 13
Every true prophet who wants to settle among you is worthy of his food. Likewise a true teacher is himself worthy, like the worker, of his food.
Therefore take every firstfruit of the produce of winepress and threshing floor, of oxen and sheep, and give the firstfruit to the prophets; for they are your high priests. But if you have no prophet, give to the poor.
Greek
Πᾶς δὲ προφήτης ἀληθινὸς θέλων καθῆσθαι πρὸς ὑμᾶς ἄξιός ἐστι τῆς τροφῆς αὐτοῦ. ὡσαύτως διδάσκαλος ἀληθινός ἐστιν ἄξιος καὶ αὐτὸς ὥσπερ ὁ ἐργάτης τῆς τροφῆς αὐτοῦ. πᾶσαν οὖν ἀπαρχὴν γεννημάτων ληνοῦ καὶ ἅλωνος, βοῶν τε καὶ προβάτων λαβὼν δώσεις τὴν ἀπαρχὴν τοῖς προφήταις· αὐτοὶ γάρ εἰσιν οἱ ἀρχιερεῖς ὑμῶν. ἐὰν δὲ μὴ ἔχητε προφήτην, δότε τοῖς πτωχοῖς.