WLC Q.170: How do they that worthily communicate in the Lord’s supper feed upon the body and blood of Christ therein?
As the body and blood of Christ are not corporally or carnally present in, with, or under the bread and wine in the Lord’s supper, (Acts 3:21) and yet are spiritually present to the faith of the receiver, no less truly and really than the elements themselves are to their outward senses; (Matt. 26:26,28) so they that worthily communicate in the sacrament of the Lord’s supper, do therein feed upon the body and blood of Christ, not after a corporal and carnal, but in a spiritual manner; yet truly and really, (1 Cor. 11:24–29) while by faith they receive and apply unto themselves Christ crucified, and all the benefits of his death. (1 Cor. 10:16)
WCF 29.7.
Worthy receivers, outwardly partaking of the visible elements, in this sacrament, (1 Cor. 11:28) do then also, inwardly by faith, really and indeed, yet not carnally and corporally but spiritually, receive, and feed upon, Christ crucified, and all benefits of His death: the body and blood of Christ being then, not corporally or carnally, in, with, or under the bread and wine; yet, as really, but spiritually, present to the faith of believers in that ordinance, as the elements themselves are to their outward senses. (1 Cor. 10:16)