The presence of the Lord’s body and blood in the bread and wine of the Lord’s Supper is real though spiritual and mysterious. This koinonia, communion by intimate participation (Cf.1 Cor. 10:15-17), with the body and blood of Christ is not a mere object lesson or heightened remembrance about a gift, it is the body and the blood.
When we gather for Lord’s Day worship, we have a mystical experience with our union with Christ. In worship we are ushered into the heavenlies by the Holy Spirit having come to Mount Zion, the heavenly Jerusalem where innumerable angels gather festively, this is the assembly of all who are enrolled in heaven (Heb 12.22-24). This is not a spatial transportation of our disembodied souls into heaven, but a breaking in of the age to come upon this present age by the Holy Spirit who indwells and maintains our union with Christ in heaven. Already we are mystically united to the body and blood of Christ through faith so our participation in His body and blood in the supper is an experience of this mystical union.
In the Lord’s Supper, we feast on Christ by the person of the Holy Spirit, partaking of Him not by the mouth, but by the Spirit through faith. But make no mistake, we really are partakers of His true body and blood by the working of the Holy Spirit. Now you might ask, how does this exactly happen? Well, with John Calvin, we will say, “It’s a mystery. We cannot explain it, but we believe it.” Our partaking of the Lord’s Supper is a spiritual connection with the past work of Christ on the cross but also with the present spiritual work of Christ, alive in Glory. So while Christ is not bodily or locally present in the Supper (His Body is only locally in heaven since His Ascension), the entire person of Christ is yet spiritually present and His Body and Blood are enjoyed in true fellowship with Him.
The Lord’s Supper is a life-giving, grace-imputing influence to the believer by the power of the Holy Spirit which is accessed by the believer’s faith recognizing the Body of the Lord in the elements and accompanied by real cautions against a casual or indifferent attitude (cf. 1 Cor. 11:27-29). While it is quite a mystery something very real, spiritual and efficacious is happening in the grace received in the Supper of an ever closer fellowship with Christ and ever increasing assurance of Salvation.