As Christ said, "by your words thou shalt be condemned."
The one-time sacrifice of Christ on the cross has been offered to God and accepted by God for all the sins of Christ's flock.
From henceforth expecting till his enemies be made his footstool. For by one offering he hath perfected for ever them that are sanctified. Whereof the Holy Ghost also is a witness to us: for after that he had said before, This is the covenant that I will make with them after those days, saith the Lord, I will put my laws into their hearts, and in their minds will I write them; And their sins and iniquities will I remember no more. Now where remission of these is, there is no more offering for sin." -- Hebrews 10:12-18"But this man, after he had offered one sacrifice for sins for ever, sat down on the right hand of God;
Thus, the Lord's Supper is a memorial; a sign and seal of the salvation Christ won for us on the cross.
Not a perpetual sacrifice as if the first one wasn't enough.