Augustine of Hippo
Catena Aurea · Johannesevangelium 17
I have manifested thy name unto the men which thou gavest me out of the world: thine they were, and thou gavest them me; and they have kept thy word. Now they have known that all things whatsoever thou hast given me are of thee. For I have given unto them the words which thou gavest me: and they have received them, and have known surely that I came out from thee, and they have believed that thou didst send me.
(Tr. cvi. c. 6) i. e. have understood and remembered them. For then is a word received, when the mind apprehends it; as it follows, And have known surely that I came out from Thee. And that none might imagine that that knowledge was one of sight, not of faith, He adds, And they hare believed (surely, is understood) that Thou didst send Me. What they believed surely, was what they knew surely; for, I came out from Thee, is the same with, Thou didst send Me. They believed surely, i. e. not as He said above they believed1, but surely, i. e. as they were about to believe firmly, steadily, unwaveringly: never any more to be scattered to their own, and leave Christ. The disciples as yet were not such as He describes them to be in the past tense, meaning such as they were to be when they had received the Holy Ghost. The question how the Father gave those words to the Son, is easier to solve, if we suppose Him to have received them from the Father as Son of man. But if we understand it to be as the Begotten of the Father, let there be no time supposed previous to His having them, as if He once existed without them: for whatever God the Father gave God the Son, He gave in begetting.