Part 1, along with some introductory remarks, is here; but I’ve also included the first paragraph of the translation in this post so that the argument is easier to follow.
Bucer to Bullinger on the Lord’s Supper
Concerning your confession: When you make the dispute a matter of the spiritual and carnal presence of Christ in the Supper, you show that you do not yet understand where the point of controversy is located. For no one defends a carnal presence. Thus no one demands that we say that the bread is the body of Christ, and all approve of taking care that the simple not venerate the signs instead of the realities. The contention is this: Since the words, “Take, eat, this is my body” etc. are the words of the Lord who gives–and not bread only, but also his body, which was handed over for us–and since Christ says these things through us, his ministers, he uses us as the stewards of his mysteries, so that we might believe and confess that the very body of the Lord is given in the sacred Supper together with the bread (that is, the exhibitive sign), just as regeneration is given together with the water of baptism, and in former times communion in the divine covenant was given through circumcision, the Holy Spirit was given together with the breath of the Lord, and the blessing of the Lord and various gifts were given together with the laying on of hands. The Passover was a commemorative, not an exhibitive, sign.
If the minister gives nothing other than the sign, he will not dispense the mysteries of God, he will not be a minister of the New Testament, he will not save, he will not regenerate. These are all things that the Apostle attributes to the sacred ministry–but in such a way that he at the same time affirms that we can devise none of these things from ourselves as ourselves, much less do them. For we are not the Lord’s ministers unless we cooperate with him in planting and watering and building, that is, in the regeneration of the saints–which surely does not consist in the words and signs without the Spirit, without true communion with Christ. Paul boasts that he laid the foundation among the Corinthians, not sacred words and signs alone; that he begot them unto the Lord through the gospel, not that he administered words alone. But it does not follow from this that we do not receive all our salvation by faith alone or that our salvation is not entirely the work of Christ alone. Christ speaks and acts in his minister, and that which Christ says and does through his minister is received by faith; and he in whom Christ does not speak and do all things is not the minister of Christ. It is therefore a fallacious argument relying on an ignorance of how refutation works to say, “Christ is eaten through faith alone; therefore he is not eaten through the service of the minister.” That is like saying, “We receive food to our advantage through attractive power alone; therefore, we do not eat through the service of the cook.” But what need is there for writing what I have learned so many times by experience to be pointless?