3 “For the Father loves the Son, and shows Him all things that Himself does.” To that which He said above, “except what He sees the Father doing,” seems to belong this also, “He shows Him all things that Himself does.” But if the Father does show what He does, and the Son cannot do except the Father has shown, and if the Father cannot show unless He has done, it will follow that it is not through the Son that the Father does all things; moreover, if we hold it fixed and unshaken, that the Father does all by the Son, then He shows the Son before He does.
For if the Father does show to the Son after He has done, that the Son may do the things shown, which being shown were already done, then doubtless something there is that the Father does without the Son. But the Father does not anything without the Son, because the Son of God is God's Word, and all things were made by Him. It remains, then, that possibly what the Father is about to do, He shows as about to be done, that it may be done by the Son. For if the Son does those things which the Father shows as already done, surely it is not by the Son that the Father has done the things which He thus shows.
For they could not be shown to the Son unless they were first done, and the Son would not be able to do them unless they were first shown; therefore were they made without the Son. But yet it is a true thing, “All things were made by Him;” therefore they were shown before they were made. But this we said must be put off, and returned to after briefly scanning the passage, if, as we said, some portion of time and of strength should remain to us for a reconsideration of the matters deferred.
Source: Tractates on the Gospel of John (New Advent)