Matthew
Matthew 26:33ESV·traditional attribution

Peter answered him, “Though they all fall away because of you, I will never fall away.”

John Calvin Reformed @genevareformer

33. Peter answering. Though Peter uses no hypocrisy, but speaks with sincere affection, yet as a false confidence in his virtue carries him away into foolish boasting, he is justly reproved by Christ, and shortly afterwards is severely punished for his rashness. Thus the event showed, that Peter promised more for himself than he was able to accomplish, because he had not been sufficiently careful to examine himself.

John Gill Reformed Baptist @doctorgill

Jesus said unto him, verily I say unto thee,.... Christ, the more strongly to asseverate what he was about to say, uses the word verily, or prefixes his "Amen" to it, as being a certain truth, and what Peter might assure himself of would certainly come to pass: that this night before the cock crow, thou shalt deny me thrice; which is, as if he...

Albert Barnes Presbyterian @notesbybarnes

Verse 33. Peter answered--though all, etc. The word men is improperly inserted here by the translators. Peter meant only to affirm this of the disciples. This confidence of Peter was entirely characteristic. He was ardent, sincere, and really attached to his Master. Yet this declaration was made, evidently: (1.) From true love to Jesus. (2.) From too much reliance on his own strength.