3 We have now, therefore, to understand, so far as He is pleased to unfold it, the meaning of the words, “Yet a little while, and the world sees me no more; but you shall see me.” It is true, indeed, that after a little while He was to withdraw even His body, in which the ungodly also were able to see Him, from their sight; for none of them saw Him after His resurrection. But since it was declared on the testimony of angels, “He shall so come in like manner as you have seen Him go into heaven;” and our faith stands to this, that He will come in the same body to judge the living and the dead; there can be no doubt that He will then be seen by the world, meaning by the name, those who are aliens from His kingdom.
And, on this account, it is far better to understand Him as having intended to refer at once to that epoch, when He said, “Yet a little while, and the world sees me no more,” when in the end of the world He shall be taken away from the sight of the damned, that for the future He may be seen only of those with whom, as those that love Him, the Father and Himself are making their abode. But He said, “a little while,” because that which appears tedious to men is very brief in the sight of God: for of this same “little while” our evangelist, John, himself says, “Little children, it is the last time.”
Source: Tractates on the Gospel of John (New Advent)