Peter, the ardent and impetuous apostle who wanted to find out right away who the betrayer was, perhaps to reprove him and prevent him from carrying out his infamous plan. 

It never entered his mind that he, too, could fall into the snare of temptation. His love for the Master was great and sincere, but presumptuous; he was too sure of himself; 

Peter needed to learn that no one can consider himself better than others, not even better than traitors.

Peter’s denial,  should serve as warning to all of us. No one can consider himself sure of not falling.