John Chrysostom

"And He came and found them asleep." For besides that it was late at night, their eyes also were weighed down by their despondency. And the third time He went and spake the same thing, establishing the fact, that He was become man. For the second and third time is in the Scriptures especially indicative of truth; like as Joseph also said to Pharaoh, "Did the dream appear to thee the second time? …

Homily on the Gospel of Matthew 83 ↗

Theophylact of Ohrid

Then cometh He to His disciples, and saith unto them, Sleep on now, and take your rest: behold, the hour is at hand, and the Son of Man is betrayed into the hands of sinners. Rise, let us be going: behold, he is at hand that doth betray Me. Showing that He has no need of their help, even when He is about to be betrayed, He says to them, "Sleep on now." Or, He is speaking with irony, as if to say, "Behold, the betrayer is at hand - sleep, if you so desire and time allows." Then He rouses them from that place where He was praying and …

Commentary on Matthew ↗

Augustine of Hippo

This speech as Matthew has it seems self-contradictory. For how could He say, Sleep on, and take your rest, and immediately continue, Rise, let us be going. This contradiction some have endeavoured to reconcile by supposing the words, Sleep on, and take your rest, to be an ironical rebuke, and not a permission; it might be rightly so taken if need were. …

Catena Aurea by Aquinas ↗

Jerome

Then he came to his disciples and said to them: Sleep now, and rest: behold, the hour is at hand, and the Son of man shall be delivered into the hands of sinners (Matthew 26 and 2 Corinthians 13). After he had prayed three times, that every word might stand in the mouth of two or three witnesses, and had obtained by subsequent penance that the fear of the apostles be corrected, he proceeds secure in his passion to his persecutors, and offers himself to be put to death, and says to his disciples:

Commentary on Matthew ↗

Hilary of Poitiers

After His persevering prayer, after His departures and several returns, He takes away their fear, restores their confidence, and exhorts them to sleep on, and take their rest. Or, He bids them sleep on, and take their rest, because He now confidently awaited His Father's will concerning the disciples, concerning which He had said, Thy will be done, and in obedience to which He drunk the cup that was to pass from Him to us, diverting upon Himself the weakness of our body, the terrors of dismay, and even the pains of death itself. …

Catena Aurea by Aquinas ↗