Augustine of Hippo

(Tr. lxiv. 1) It may be understood too thus: I am as yet in this frail flesh, even as ye are, until I die and rise again. He was with them after His resurrection, by bodily presence, not by participation of human frailty. These are the words which I spake unto you, while I was yet with you, (Luke 24:44) He says to His disciples after His resurrection; meaning, while I was in mortal flesh, as ye are. He was in the same flesh then with them, but not subject to the same mortality. But there is another Divine Presence unknown to mortal senses, of which He saith, Lo, I am with you alway, even unto the end of the world. (Mat. 28:20) This is not the presence meant by, A little while I am with you; for it is not a little while to the end of the world: or even if it is a little while, because that in the eye of God, a thousand years are as one day, yet what follows shews that it is not what our Lord is here alluding to; for He adds, Whither I go ye cannot follow Me now. At the end of the world they were to follow Him, whither He went; as He saith below; Father, I will that they be with Me, where I am. (c. 17:24)