Peter said to him [Jesus], “Master, why can’t I follow you now? I will lay down my life for you.” Jesus answered, “Will you lay down your life for me? Amen, amen, I say to you, the cock will not crow before you deny me three times.” (John 13:37-38)

Peter is sincere in his pledge, but he succumbs to the relentless lure of presumption. Even the most courageous will not remain faithful to allegiance without divine assistance. Like others, Peter will be unable to watch and pray even one hour. Later when Jesus is arrested, Peter will flee in trembling and fear. In the courtyard fear seizes Peter and he denies Jesus three times. As the cock crows, the blinding scales of stubborn self-reliance fall and Peter remorsefully acknowledges his frailty and need for divine mercy.

As long as a soul depends entirely upon itself, it is unready to be sanctified and, furthermore, unable to be an effective instrument of sanctification of others.