6 “And you have believed,” He adds, “that I came out from God. I came forth from the Father, and have come into the world: again I leave the world, and go to the Father.” Clearly we have believed. For surely it ought not to be accounted a thing incredible because of this, that in coming to the world He came forth in such a sense from the Father that He did not leave the Father behind; and that, on leaving the world, He goes to the Father in such a sense that He does not actually forsake the world. For He came forth from the Father because He is of the Father; and He came into the world, in showing to the world His bodily form, which He had received of the Virgin. He left the world by a bodily withdrawal, He proceeded to the Father by His ascension as man, but He forsook not the world in the ruling activity of His presence.
Source: Tractates on the Gospel of John (New Advent)