Didache — Didache 7
And concerning baptism, baptize this way: Having first said all these things, baptize into the name of the Father, and of the Son, and of the Holy Spirit, Matthew 28:19 in living water. But if you have not living water, baptize into other water; and if you can not in cold, in warm. But if you have not either, pour out water thrice upon the head into the name of Father and Son and Holy Spirit. But before the baptism let the baptizer fast, and the baptized, and whatever others can; but you shall order the baptized to fast one or two days before.
Greek
Περὶ δὲ τοῦ βαπτίσματος, οὕτω βαπτίσατε: Mt. 28, 19 ταῦτα πάντα προειπόντες, βαπτίσατε εἰς τὸ ὄνομα τοῦ πατρὸς καὶ τοῦ υἱοῦ καὶ τοῦ ἁγίου πνεύματος ἐν ὕδατι ζῶντι.
ἐὰν δὲ μὴ ἔχῃς ὕδωρ ζῶν, εἰς ἄλλο ὕδωρ βάπτισον: εἰ δ’ οὐ δύνασαι ἐν ψυχρῷ, ἐν θερμῷ.
ἐὰν δὲ ἀμφότερα μὴ ἔχῃς, ἔκχεον εἰς τὴν κεφαλὴν τρὶς ὕδωρ εἰς Mt. 28, 12 ὄνομα πατρὸς καὶ υἱοῦ καὶ ἁγίου πνεύματος.
πρὸ δὲ τοῦ βαπτίσματος προνηστευσάτω ὁ βαπτίζων καὶ ὁ βαπτιζόμενος καὶ εἴ τινες ἄλλοι δύνανται: κελεύεις δὲ νηστεῦσαι τὸν βαπτιζόμενον πρὸ μιᾶς ἢ δύο.