Charles Ellicott Commentary Matthew 26:33

"But Peter answered and said unto him, If all shall be offended in thee, I will never be offended." — Matthew 26:33 (ASV)

Though all men shall be offended — St. Matthew and St. Mark place the boast of Peter, and the prediction of his denial, after the disciples had left the guest-chamber; St. Luke (Luke 22:23) and St. John (John 13:37) agree in placing it before. It is barely possible that both may have been repeated, but the more probable hypothesis is that we have here an example of the natural dislocation of the exact order of events that followed one upon another in rapid sequence, and at a time when the disciples’ minds were heavy with confused sorrow.