Of Prayer, by John Calvin, tr. Henry Beveridge , at sacred-texts.com
On the whole, since Scripture places the principal part of worship in the invocation of God (this being the office of piety which he requires of us in preference to all sacrifices), it is manifest sacrilege to offer prayer to others. Hence it is said in the psalm: "If we have forgotten the name of our God, or stretched out our hands to a strange god, shall not God search this out?" (Ps. 44:20, 21). Again, since it is only in faith that God desires to be invoked, and he distinctly enjoins us to frame our prayers according to the rule of his word: in fine, since faith is founded on the word, and is the parent of right prayer, the moment we decline from the word, our prayers are impure. But we have already shown, that if we consult the whole volume of Scripture, we shall find that God claims this honour to himself alone. In regard to the office of intercession, we have also seen that it is peculiar to Christ, and that no prayer is agreeable to God which he as Mediator does not sanctify. And though believers mutually offer up prayers to God in behalf of their brethren, we have shown that this derogates in no respect from the sole intercession of Christ, because all trust to that intercession in commending themselves as well as others to God. Moreover, we have shown that this is ignorantly transferred to the dead, of whom we nowhere read that they were commanded to pray for us. The Scripture often exhorts us to offer up mutual prayers; but says not one syllable concerning the dead; nay, James tacitly excludes the dead when he combines the two things, to "confess our sins one to another, and to pray one for another" (James 5:16). Hence it is sufficient to condemn this error, that the beginning of right prayer springs from faith, and that faith comes by the hearing of the word of God, in which there is no mention of fictitious intercession, superstition having rashly adopted intercessors who have not been divinely appointed. While the Scripture abounds in various forms of prayer, we find no example of this intercession, without which Papists think there is no prayer. Moreover, it is evident that this superstition is the result of distrust, because they are either not contented with Christ as an intercessor, or have altogether robbed him of this honour. This last is easily proved by their effrontery in maintaining, as the strongest of all their arguments for the intercession of the saints, that we are unworthy of familiar access to God. This, indeed, we acknowledge to be most true, but we thence infer that they leave nothing to Christ, because they consider his intercession as nothing, unless it is supplemented by that of George and Hypolyte, and similar phantoms.