As we meditate on the Word of God that accompanies the sacrament, we have to take care that we pray for the Word to teach us fully, which is to say, richly and mysteriously.
You commune with the Lord, one with Him through the agency of the Holy Spirit, and in this communion, this partaking, this koinonia, You are being built up into a perfect bride, without spot or wrinkle, or any other blemish. There is a particular communion in this Supper, a particular grace, that is not available elsewhere in other settings.
The apostle Paul compares it, with some hesitant qualification, to sexual communion within marriage. This is like that, he says, and it is all a great mystery. We want to speak about this carefully, because St. Paul does, but we also want to speak about it clearly, because Paul does. Just as a married couple are married all the time, and are one with one another all the time, so also there are particular times when that union is particularly expressed in sexual communion.
There is a comparison that must be made to the Lord’s Supper. You are one with Christ all the time. You have fellowship with Him all the time. You may pray to Him at any time. You are part of the bride of Christ all the time. But God in His grace has given us the privilege of renewing covenant with Him in this way, regularly, not because we are any less married to Christ if we do not, but because that marriage is languishing if we do not.
Again, this is all a great mystery, and all the more reason, therefore, to approach God in this way, seeking to be edified and built up in that mystery.