If Judas is the classic example of the vine branch that withers and is cut out, Peter the Apostle is the vine branch which is pruned. “I am the true vine, and my Father is the vine-grower….Every branch that bears fruit he prunes to make it bear more fruit” (NRSV, John 15:2).

Peter’s confidence in Our Lord, which bound him to his Master, was firm enough for him to be the first to declare the secret of his identity. “You are the Messiah, the Son of the living God” (NRSV, Matthew 16:16). But Peter’s confidence was not so unquestioning that he was prepared unreservedly to accept Our Lord’s judgement and to follow wherever it led.

So when, immediately afterwards, Jesus went on to tell the disciples how he must go to Jerusalem and be crucified, Peter rebuked him saying, “God forbid it, Lord! This must never happen to you” (NRSV, Matthew 16:22).

At this stage he preferred Our Lord’s will to his own only in principle: his confidence was still shallow enough, for him on particular issues to insist what that will in his opinion ought to be. And just as Judas Iscariot’s lack of trust severed his union with Our Lord and led to his betrayal of his Master; so the feebleness of Peter’s trust weakened his union and led to his denial.