Didache: But concerning baptism . . .
“But concerning baptism, thus baptize ye: having first recited all these precepts, baptize in the name of the Father, and of the Son, and of the Holy Spirit, in running water; but if thou hast not running water, baptize in some other water, and if thou canst not baptize in cold, in warm water; but if thou hast neither, pour water three times on the head, in the name of the Father, and of the Son, and of the Holy Spirit.
But before the baptism, let him who baptizeth and him who is baptized fast previously, and any others who may be able. And thou shalt command him who is baptized to fast one or two days before.”
+ The Didache (Teaching of the Twelve), Chapter 7