The Covenant is founded simply on the bloodshed of One for many for the remission of sins, without any other element, whether in the form of supposed merit, or moral improvement, or services performed as the procuring cause. The cup of Thanksgiving was thus the evidence of our participation by faith in the blood of Christ and the bread that participation by faith in the body of Christ, as our only acceptance before God. The sacrament of the supper loudly proclaims this great truth to all time, and all ages must hear it. Till the Lord come, His atoning death must be proclaimed with festive Joy at this supper, as often as it is deemed proper to celebrate it. Of how great importance must that truth be which Jesus so vividly portrayed, and the perpetual memory of which He has so carefully secured! This shows what a supreme place belongs to His atoning sacrifice. It is the principal thing of the Gospel; nay, it is the Gospel. Take it out of the Gospel and it ceases to be the Gospel.
George Smeaton, from The Doctrine of the Atonement According to the Apostles.