Augustine of Hippo
Catena Aurea · Johannesevangelium 2
His mother saith unto the servants, Whatsoever he saith unto you, do it. And there were set there six waterpots of stone, after the manner of the purifying of the Jews, containing two or three firkins apiece. Jesus saith unto them, Fill the waterpots with water. And they filled them up to the brim. And he saith unto them, Draw out now, and bear unto the governor of the feast. And they bare it. When the ruler of the feast had tasted the water that was made wine, and knew not whence it was: (but the servants which drew the water knew;) the governor of the feast called the bridegroom, And saith unto him, Every man at the beginning doth set forth good wine; and when men have well drunk, then that which is worse: but thou hast kept the good wine until now. This beginning of miracles did Jesus in Cana of Galilee, and manifested forth his glory; and his disciples believed on him. Jesus saith unto them, Fill the waterpots with water. And they filled them up to the brim.
(de Cons. Evang. l. ii c. xvii. [38.]) If now for the first time they believed on Him, they were not His disciples when they came to the marriage. This however is a form of speech, such as saying that the Apostle Paul was born in Tarsus of Cilicia; not meaning by this that he was an Apostle then. In the same way when we hear of Christ’s disciples being invited to the marriage, we should understand not disciples already, but who were to be disciples.