Tractates on the Gospel of John

⁴ “In that day,” He says, “you shall know that I am in my Father, and you in me, and I in you.” In what day, but in that whereof He said, “You shall live also”? For then will it be that we can see what we believe. For even now is He in us, and we in Him: this we believe now, but then shall we also know it; although what we know even now by faith, we shall know then by actual vision. For as long as we are in the body, as it now is, to wit, corruptible, and encumbering to the soul, we live at a distance from the Lord; for we walk by faith, not by sight. Then accordingly it will be by sight, for we shall see Him as He is. For if Christ were not even now in us, the apostle would not say, “And if Christ be in you, the body is dead indeed because of sin; but the spirit is life because of righteousness.” But that we are also in Him even then, He makes sufficiently clear, when He says, “I am the vine, you are the branches.” Accordingly in that day, when we shall be living the life, whereby death shall be swallowed up, we shall know that He is in the Father, and we in Him, and He in us; for then shall be completed that very state which is already in the present begun by Him, that He should be in us, and we in Him.