We see later on, more than once, that when the disciples were questioning among themselves who should be the greatest, Peter was one of them. He thought he had a right to the very first place. He sought his own honor even above the others. The life of self was strong in Peter. When Christ had spoken to him about His sufferings and said, “Get behind me, Satan,”He followed it up by saying, “If anyone would come after me, he must deny himself and take up his cross and follow me.”No man can follow Him unless he does that. Self must be utterly denied. What does this mean? When Peter denied Christ, three times he said he didn’t know the man. In other words, “I have nothing to do with Him; He and I are not friends; I deny having any connection with Him.”Christ told Peter that he must deny himself. Self must be ignored and its every claim rejected. That is the root of true discipleship; but Peter did not understand it and could not obey it.
Consequently, when the last night came, Christ said to him, “Before the rooster crows today, you will disown me three times.”But with what self-confidence Peter said, “Lord, I am ready to go with you to prison and to death.”Peter truly meant it and really intended to do it; but Peter didn’t know himself. Perhaps we do not know ourselves so well either. Do we give place to our self-life? What have we done with our flesh, entirely under the power of sin? Deliverance from that is what we need. Peter did not understand this, and therefore in self-confidence he even denied his Lord. Notice how Christ used that word deny twice. He said to Peter the first time, Deny yourself; and the second time, You will deny me (disown, as some translations have it). It is either one or the other. There is no alternative; we must either deny self or deny Christ. There are two great powers fighting each other—the self-life in the power of sin, and Christ in the power of God. One of these must rule within us."
Absolute Surrender by Murray, Andrew