1 The words of our Lord Jesus Christ, especially those recorded by the Evangelist John,— who not without cause leaned on the Lord's bosom, that he might drink in the secrets of that higher wisdom, and by evangelizing give forth again what by loving he had drunk in—are so secret and profound of understanding, that they trouble all who are perverse of heart, and exercise all who are in heart upright. Wherefore, beloved, give heed to these few words that have been read. Let us see if in any wise we can, by His own gift and help who has willed His words to be recited to us, which at that time were heard and committed to writing that they might now be read, what He means in what you have now heard Him say: “Verily, verily, I say unto you, The Son cannot of Himself do anything, but what He sees the Father doing: for what things soever the Father does, these same the Son also does in like manner.”
Source: Tractates on the Gospel of John (New Advent)