8 And now see how the disciples were terrified at His words. The disciples say unto Him, Master, the Jews of late sought to stone You, and You are going there again? Jesus answered, Are there not twelve hours in the day? What does such an answer mean? They said to Him, “The Jews of late sought to stone You, and You are going there again” to be stoned? And the Lord, “Are there not twelve hours in the day? If any man walk in the day, he stumbles not, because he sees the light of this world: but if he walk in the night, he stumbles, because there is no light in him.”
He spoke indeed of the day, but to our understanding as if it were still the night. Let us call upon the Day to chase away the night, and illuminate our hearts with the light. For what did the Lord mean? As far as I can judge, and as the height and depth of His meaning breaks into light, He wished to argue down their doubting and unbelief. For they wished by their counsel to keep the Lord from death, who had come to die, to save themselves from death. In a similar way also, in another passage, St.
Peter, who loved the Lord, but did not yet fully understand the reason of His coming, was afraid of His dying, and so displeased the Life, to wit, the Lord Himself; for when He was intimating to the disciples what He was about to suffer at Jerusalem at the hands of the Jews, Peter made reply among the rest, and said, “Far be it from You, Lord; pity Yourself: this shall not be unto You.” And at once the Lord replied, “Get behind me, Satan: for you savor not the things that be of God, but those that be of men.”
And yet a little before, in confessing the Son of God, he had merited commendation: for he heard the words, “Blessed are you, Simon Barjona: for flesh and blood has not revealed it unto you, but my Father who is in heaven.” To whom He had said, “Blessed are you,” He now says, “Get behind me, Satan;” because it was not of himself that he was blessed. But of what then? “For flesh and blood has not revealed it unto you, but my Father who is in heaven.” See, this is how you are blessed, not from anything that is your own, but from that which is mine.
Not that I am the Father, but that all things which the Father has are mine. But if his blessedness came from the Lord's own working, from whose [working] came he to be Satan? He there tells us: for He assigned the reason of such blessedness, when He said, “Flesh and blood has not revealed this unto you, but my Father who is in heaven:” that is the cause of your blessedness. But that I said, “Get behind me, Satan, hear also its cause. For you savor not the things that be of God, but those that be of men.”
Let no one then flatter himself: in that which is natural to himself he is Satan, in that which is of God he is blessed. For all that is of his own, whence comes it, but from his sin? Put away the sin, which is your own. Righteousness, He says, belongs unto me. For what have you that thou did not receive? Accordingly, when men wished to give counsel to God, disciples to their Master, servants to their Lord, patients to their Physician, He reproved them by saying, “Are there not twelve hours in the day?
If any man walk in the day, he stumbles not.” Follow me, if you would not stumble: give not counsel to me, from whom you ought to receive it. To what, then, refer the words, “Are there not twelve hours in the day”? Just that to point Himself out as the day, He made choice of twelve disciples. If I am the day, He says, and you the hours, is it for the hours to give counsel to the day? The day is followed by the hours, not the hours by the day. If these, then, were the hours, what in such a reckoning was Judas?
Was he also among the twelve hours? If he was an hour, he had light; and if he had light, how was the Day betrayed by him to death? But the Lord, in so speaking, foresaw, not Judas himself, but his successor. For Judas, when he fell, was succeeded by Matthias, and the duodenary number preserved. It was not, then, without a purpose that the Lord made choice of twelve disciples, but to indicate that He Himself is the spiritual Day. Let the hours then attend upon the Day, let them preach the Day, be made known and illuminated by the Day, and by the preaching of the hours may the world believe in the Day. And so in a summary way it was just this that He said: Follow me, if you would not stumble.
Source: Tractates on the Gospel of John (New Advent)