Paul represents (Romans 2:29) circumcision as of letter and spirit. We must think similarly of baptism. Some carry in their bodies the mere sign, but are far from possessing the reality. For Peter also, teaching that salvation follows our baptism, immediately adds as though in correction that the mere external washing of the flesh is not enough unless there is added also the answer of a good conscience (I Peter 3:21).
Thus Scripture, in dealing with the sacraments, customarily speaks of them in a twofold sense. When dealing with hypocrites who glory in the sign and neglect the reality, in order to prostrate [throw down] their confidence, it separates the reality from the signs, in contrast to their perverse understanding. Thus Paul (I Cor 10:3-13) reminds his readers that it did not profit the ancient people to have been baptized in their passage through the Red Sea and to have with us the same spiritual food in the desert (meaning, that is, that they participated with us in the same external signs of the spiritual gifts).
But addressing the faithful he describes the use of the sacraments as legitimate, efficacious and corresponding to the divine institution. It is here that phrases apply: to have put on Christ, engrafted into His body, buried together with him, who have been baptized in His name (Rom. 6:4, Col 2:12, Gal. 3:27, I Cor. 12:27). From [these passages] Pighius concludes that all sprinkled with the visible element of water are truly regenerated by the Spirit and incorporated into the body of Christ so as to live to God and in His righteousness...
But a little later, as if drawing in his wings, Pighius remarks that many fall away from Christ who had been truly engrafted into His body; for he makes out that those committed to Christ and received into His faithful care are saved by Him in such a way that their salvation is dependent on their own free will. To many, he says, the protecting grace of Christ is not wanting, but they are wanting in themselves. Certainly the stupidity and ingratitude of those who withdraw themselves from the help of God can never be sufficiently condemned. But it is a quite intolerable insult to Christ to say that the elect are saved by Him, provided they look after themselves. This is to render doubtful the protection of Christ which He affirms is invincible against the devil and all the machinations of hell. Christ promised to give eternal life to all give Him by the Father (John 17:2). He testifies that He is a faithful custodian of them all, so that none perishes except the son of perdition (John 17:12)…
If eternal life is certain to all the elect, if no one can pluck them from Him, if no violence nor any assault can tear them from Him, if their salvation stands in the invincible power of God, what impudence for Pighius to shake so fixed a certitude. Though Christ casts none out, he says, yet many depart from Him, and those who once were children of God do not continue so. But Pighius is a bad and perverse interpreter, not acknowledging that whatever is given him by the Father is retained in the hand of Christ, so that it remains safe to the end; for those that fall away, John declares to be not of His flock.
This lengthy quote is worth reading carefully for several reasons. It shows that certain lines from Calvin, such as “yet many depart from Him, and those who once were children of God do not continue so” can be interpreted out of context to mean something they do not mean. This line, by itself, sounds like Calvin believes true Christians can fall away. However, throughout the passage and the book he draws a clear line between the elect and the non-elect while still agreeing that “many things are found alike in the reprobate and the children of God. But, however they shine in appearance of righteousness, it is certain they are not possessed of the Spirit of adoption, so that their owners may truly invoke God as Father.” (This quote is two pages after the one above.) While there are some similarities with the elect, those who fall away are never part of the elect in the fullest sense. They are not adopted and God is not their Father.
This passage also shows that the relationship between election and the sacraments has long been an issue. Pighius argued that the elect were saved at baptism, but the rest was left up to them. They were “regenerated by the Spirit.” They have been truly grafted into Christ’s body, but they must keep themselves there. Calvin says God gives all to his elect, including the promise that Christ is the “faithful custodian of them.” Those given to Christ by the Father are kept by Christ unto the end. There are none lost (John 6:39).
Calvin gives the classic understanding of how the sacraments are to be understood. There is the sign (baptism/communion/the Word) and there is the reality, Jesus Christ received by faith. Hypocrites need to have the two distinguished so they do not glory in the sign while not having the reality. The faithful need to have the two wedded together so they do not despair, but know that Jesus really feeds them through these signs.
Finally, he makes clear that Christ’s power and glory are at stake in any debate about election. Predestination debates are not primarily about man’s free will, but about the power of Christ to save and redeem. When we say man can and does slip from Christ’s grasp the primary problem is not that we grant man a completely free will, but that we deny the efficacy of Christ’s work.