Without the presence and work of the Holy Spirit, this sacrament is nothing more than a religious snack—to put it crudely. It would be a nice communal ritual, but nothing more than eating a piece of bread and drinking a thimble of wine together.
This is true in two ways:
First, without the regenerating work of the Spirit in our hearts, we would all still be dead in our sins without faith. To approach this Table without faith in Christ is to receive empty symbols. Unbelievers may take hold of the bread and wine, but without the gift of faith, they do not truly take hold of Christ. Rather, as Scripture warns, to partake of this covenantal meal in an unworthy manner is to drink the judgment of God, to trample on the blood of Christ (1 Cor. 11:27, Heb. 10:29).
The second way that the Spirit is essential is that He lifts us up to Christ, who is enthroned in heaven at the right hand of the Father. Because our Lord has bodily ascended to heaven, we do not believe that this bread and wine transform into His body and blood or that He is somehow physically and locally present in or around these elements. Instead, it is the Spirit who spiritually unites us to His body and enables us to receive Him in this bread and wine by faith.
As John Calvin once vividly put it, “If [the Spirit] is wanting, the sacraments can avail us no more than the sun shining on the eyeballs of the blind, or sounds uttered in the ears of the deaf.” Without the Spirit, this sacrament really is meaningless. And so today we thank God the Spirit for opening our eyes and ears of faith, to see Christ in this meal and to hear His precious Word.
So with believing hearts—come, and welcome, to Jesus Christ.