It is a commonplace of Reformed sacramental theology that the Lord’s Supper cannot be efficacious apart from faith.1 There is nothing automatically efficacious about ritual action in and of itself.
Here is a curious proof for this suggestion from a wider biblical perspective than the texts traditionally used in sacramental discussion:
In the messianic second Psalm, we find the following command, familiar to most readers:
Kiss the Son, lest he be angry, and you perish in the way, for his wrath is quickly kindled. Blessed are all who take refuge in him. (Psalm 2.12; ESV here and throughout)
Christian believers quote the beginning of this Psalm in Acts 4 as prophetic of Christ. The last verse, on the other hand, which I have quoted, is not cited in the New Testament. It is perversely echoed, however, in Judas’ betrayal of Christ:
While he was still speaking, Judas came, one of the twelve, and with him a great crowd with swords and clubs, from the chief priests and the elders of the people. Now the betrayer had given them a sign, saying, “The one I will kiss is the man; seize him.” And he came up to Jesus at once and said, “Greetings, Rabbi!” And he kissed him. Jesus said to him, “Friend, do what you came to do.” Then they came up and laid hands on Jesus and seized him. (Matt. 16.47-9)
Why bring this up? The kiss in the Psalm is a symbolic and ritualistic act, signifying subjection to the Son as King and Lord. It gains its primary force from what it represents.
The same could be said of the kiss of Judas. It is a sign (σημεῖον, the same term used by Paul in Rom. 4.11 to describe circumcision) and here functions as part of what is really an antisacrament: the betrayal of the Lord, in which Judas brings him to recognition for the purpose of high treason.
What does this tell us about ritual action in a Christian context? The bare ritual act itself is not communicative of saving and nourishing grace. Psalm 2 speaks of blessing, and yet Judas is cursed. Why? Because he did not have faith in Christ. He pantomimes the symbolic act, but in so doing brings judgment on himself.
There is something analogous to the manducatio impiorum here–call it the osculum impiorum if you like–but we should specify what is meant by this kind of term. Paul is clear in 1 Cor. 11 that there is a way to eat and drink judgment on oneself, but we wouldn’t want to say it comes from truly partaking of the body and blood of Christ. For the body and blood of Christ are saving, and whoever participates in them participates in the Savior himself, to whom he is united. One cannot be both united to Christ and damned. The one who is condemned is condemned precisely because he is not united to Christ, and does not feed upon him to eternal life.
So what makes the difference between an efficacious sacramental act and a sacrament-manqué? The word of promise and the Spirit on the divine side, obviously. And, on the human side, faith: belief and trust in Jesus as Savior and King. This is the means by which one takes refuge in him and is thereby blessed. Without it, a person remains outside of Christ, and Christ remains outside of him.
Thus Jesus responds to those who are scandalized by the Bread of Life discourse (“Truly, truly, I say to you, unless you eat the flesh of the Son of Man and drink his blood, you have no life in you”): “Do you take offense at this? Then what if you were to see the Son of Man ascending to where he was before? It is the Spirit who gives life; the flesh is of no avail. The words I have spoken to you are spirit and life. But there are some of you who do not believe” (John 6.61-2). Word, Spirit, faith: it is by these that ritual actions do not remain ritual actions merely, extrinsic to the ritual actor, but instead become the means of life.