In 1550, the Scottish Reformer John Knox wrote a brief summary of the Reformed doctrine of the Lord’s Supper. Knox entitled his document
Here is briefly declared in a summary, according to the Holy Scriptures, what opinion we Christians have of the Lord’s Supper, called the Sacrament of the body and blood of our Savior Jesus Christ.
Although this statement is only seven paragraphs in length, it is, nevertheless, brimming with rich theological insights on the doctrine of the sacrament.
One of the striking features of this treatise on the Lord’s Supper is that Jesus Christ is the subject of every sentence. Knox does not look at the Lord’s Supper as a work of man but as a work of Jesus Christ.
Christ “lifts us up unto heavenly and invisible things.” Christ “confirms and seals up to us his promise.” Christ “represents … and makes plain to our senses, his heavenly gifts.” Christ “gives unto us himself.” Christ “gathers us unto one visible body.” Christ “calls us to remembrance of his Death and Passion.”
James McEwen observed
In this little document, in a remarkable and striking way, the whole action of the Sacrament is referred to Christ. There is nothing at all about what “we” do, or what the Church does. The Sacrament is not looked on as a ministerial act, or a Churchly ordinance. It is, first and last, something that Christ does for us.
Here is Knox’s summary of what he considered to be the biblical doctrine of the Lord’s Supper.
Here is briefly declared in a summary, according to the holy scriptures, what opinion we Christians have of the Lord’s Supper, called the sacrament of the body and blood of our Saviour Jesus Christ.
First, we confess that it is a holy action, ordained of God, in the which the Lord Jesus, by earthly and visible things set before us, lifts us up unto heavenly and invisible things. And that when he had prepared his spiritual banquet, he witnessed that he himself was the lively bread wherewith our souls are fed unto everlasting life.
And therefore, in setting forth bread and wine to eat and drink, he confirms and seals up to us his promise and communion (that is, that we shall be partakers with him in his kingdom); and he represents unto us, and makes plain to our senses, his heavenly gifts; and also gives unto us himself, to be received with faith, and not with mouth, nor yet by transfusion of substance; but so, through the virtue [power] of the Holy Ghost, that we, being fed with his flesh, and refreshed with his blood, may be renewed both unto true godliness and to immortality.
And also [we confess] that herewith the Lord Jesus gathered us unto one visible body, so that we are members one of another, and make altogether one body, whereof Jesus Christ is the only Head; and, finally, that by the same sacrament, the Lord calls us to remembrance of his death and passion, to stir up our hearts to praise his most holy name.
Furthermore, we acknowledge that this sacrament ought to be come unto reverently, considering there is exhibited and given a testimony of the wonderful society and knitting together of the Lord Jesus and of the receivers; and also, that there is included and contained in this sacrament, [a testimony] that he will preserve his kirk. For herein we are commanded to show the Lord’s death until he come (1 Cor. 11:26).
Also we believe that it is a confession, wherein we show what kind of doctrine we profess; and what congregation we join ourselves unto; and likewise, that it is a bond of mutual love amongst us. And, finally, we believe that all the comers unto this holy Supper must bring with them their conversion unto the Lord, by unfeigned repentance in faith; and in this sacrament receive the seals and confirmation of their faith; and yet must in nowise think that for this work’s sake their sins are forgiven.
And as concerning these words, Hoc est corpus meum, “This is my body” (1 Cor. 11:24; Matt. 26:26; Mark 14:22; Luke 22:19), on which the Papists depend so much, saying that we must needs believe that the bread and wine are transubstantiated unto Christ’s body and blood: we acknowledge that it is no article of our faith which can save us, nor which we are bound to believe upon pain of eternal damnation. For if we should believe that his very natural body, both flesh and blood, were naturally in the bread and wine, that should not save us, seeing many believe that, and yet receive it to their damnation. For it is not his presence in the bread that can save us, but his presence in our hearts, through faith in his blood, which has washed out our sins, and pacified his Father’s wrath towards us. And again, if we do not believe his bodily presence in the bread and wine, that shall not damn us, but the absence out of our hearts through unbelief.
Now, if they would here object, that though it be truth, that the absence out of the bread could not damn us, yet are we bound to believe it because of God’s word, saying, “This is my body” (1 Cor. 11:24); which who believes not, as much as in him lies, makes God a liar; and, therefore of an obstinate mind not to believe his word, may be our damnation: To this we answer, that we believe God’s word, and confess that it is true, but not so to be understood as the Papists grossly affirm. For in the sacrament we receive Jesus Christ spiritually, as did the fathers of the Old Testament, according to St. Paul’s saying (1 Cor. 10:3–4). And if men would well weigh, how that Christ, ordaining his holy sacrament of his body and blood, spoke these words sacramentally, doubtless they would never so grossly and foolishly understand them, contrary to all the scriptures, and to the exposition of St. Augustine, St. Jerome, Fulgentius, Vigilius, Origen, and many other godly writers.
 James S. McEwen, The Faith of John Knox (London: Lutterworth Press, 1961) 56.