In Calvin’s commentary on John 13, we find a helpful discussion of Peter’s pious yet confused outburst, “Lord, [wash] not my feet only but also my hands and my head!” (John 13:9) As Calvin’s discussion (to follow) describes, we have much to learn from this little window into Peter’s mind, and ours. Some thoughts:
Pride causes many to think they do not need to be cleansed from sin’s defilement, but many Christians, pondering their remaining sin, forget what Christ has already done in making us a new creation in Him by the Spirit. By doing this, we dishonor the mighty work of God in turning our hearts to him, forgetting our prior cleansing by the Spirit.
As a Christian, both things are true: I am washed from sin by the blood of Christ and His Spirit, sealed to me in baptism. AND I continue to need his cleansing from the sins that cling to my feet. Understanding this fosters love and humility.
We ought not to pray for forgiveness as if we are not already forgiven, nor pray for help against sin as if we are not being helped. I hear this kind of praying often in our Reformed circles, and I myself have been guilty of it over and over. It is nothing less than to doubt the goodness of God. We come in our prayers of confession to a reconciled Father in Jesus Christ, not to a distant judge unwilling to receive us. The entire context of our daily confession and repentance must be faith in the loving, fatherly goodness of the Triune God of our salvation. “But you were washed…” the apostle says. “You are clean,” Jesus says.
Our mode of baptism by pouring or sprinkling appropriately pictures a washing from the top-down, where the head and body are clean but the feet (the lower parts) will need to be again washed, but the whole is clean.
Any talk of Christians being “totally depraved” is a mere repetition of Peter’s error: treating the benefits we have already received as if they are of no value.
Lord, not my feet only.
When Peter heard that he was ruined, if he did not accept the cleansing which was offered to him by Christ, this necessity proved, at length, to be a sufficient instructor to tame him. He therefore lays aside opposition and yields, but wishes to be entirely washed, and, indeed, acknowledges that, for his own part, he is altogether covered with pollution, and, therefore, that it is doing nothing, if he be only washed in one part. But here too he goes wrong through thoughtlessness, in treating, as a thing of no value, the benefit which he had already received; for he speaks as if he had not yet obtained any pardon of sins, or any sanctification by the Holy Spirit. On this account, Christ justly reproves him, for he recalls to his recollection what he had formerly bestowed on him; at the same time, reminding all his disciples in the person of one man, that, while they remembered the grace which they had received, they should consider what they still needed for the future.
He who is washed needeth not to wash more than his feet, but is altogether clean.
First, he says that believers are altogether clean; not that they are in every respect pure, so that there no longer remains in them any stain, but because they are cleansed in their chief part; that is, when sin is deprived of its kingly power, so that the righteousness of God holds the superiority; just as if we were to say, that a body was altogether healthy, Because it was not infected with any universal disease. It is by newness of life, therefore, that we must testify ourselves to be the disciples of Christ, for he declares that he is the Author of purity in all his followers.Again, the other comparison was also applied to the case in hand, that Peter might not set aside the washing of the feet as foolish; for, as Christ washes from the head to the feet, those whom he receives as his disciples, so, in those whom he has cleansed, the lower part remains to be daily cleansed. The children of God are not altogether regenerated on the first day, so as to aim at nothing but the heavenly life; but, on the contrary, the remains of the flesh continue to dwell in them, with which they maintain a continued struggle throughout their whole life. The term feet, therefore, is metaphorically applied to all the passions and cares by which we are brought into contact with the world; for, if the Holy Spirit occupied every part of us, we would no longer have anything to do with the pollutions of the world; but now, by that part in which we are carnal, we creep on the ground, or at least fix our feet in the clay, and, therefor are to some extent unclean. Thus Christ always finds in us something to cleanse. What is here spoken of is not the forgiveness of sins, but the renewal, by which Christ, by gradual and uninterrupted succession, delivers his followers entirely from the sinful desires of the flesh.
From: http://www.ccel.org/ccel/calvin/calcom35.iii.ii.html