Peter again denied it with an oath: “I do not know that man.”
This verse shows the deepening of Peter’s denial. If the first time he simply avoided speaking, now he confirms his denial with an oath. The phrase “I do not know that man” becomes even more serious, because Peter no longer says, “I do not know Jesus,” but “that man,” avoiding even speaking His name. This testifies to the inner struggle taking place between fear and conscience. His oath, as a means of self-defense, in fact deepens the sin even more, because he tries to protect himself with a lie. Yet God’s providence is at work even in this fall: Jesus allows Peter to recognize his weakness, so that in the future he may become a humble and steadfast believer, serving as an example for many followers. In addition, this episode also shows that there are situations in which a person cannot stand firm by his own strength without grace.