The following is an excerpt from an article by the Reformed Protestant R.C. Sproul.
"The drafters of the document, Charles Colson, Robert George, and Timothy George, used deliberate language that is on par with the ecumenical language of the Evangelicals and Catholics Together (ECT) movement that began in the 1990s. The Manhattan Declaration states, “Christians are heirs of a 2,000-year tradition of proclaiming God’s Word,” and it identifies “Orthodox, Catholic, and Evangelicals” as “Christians.” The document calls Christians to unite in “the Gospel,” “the Gospel of costly grace,” and “the Gospel of our Lord and Savior Jesus Christ in its fullness.” Moreover, the document says, “it is our duty to proclaim the Gospel of our Lord and Savior Jesus Christ in its fullness, both in season and out of season.”
Without question, biblical truth must be proclaimed and the gospel preached prophetically to our nation. But how could I sign something that confuses the gospel and obscures the very definition of who is and who is not a Christian? I have made this point again and again since the days of ECT. Though the framers of the Manhattan Declaration declaim any connection to ECT, it appears to me that the Manhattan Declaration is inescapably linked to that initiative, which I have strenuously resisted. More than that, this new document practically assumes the victory of ECT in using the term “the gospel” in reference to that which Roman Catholics are said to “proclaim” (Phil. 1:27).
The Roman Catholic Church has a long history of using studied ambiguity in order to win over opponents. Let me be unambiguous: Without a clear understanding of sola fide and the doctrine of the imputation of Christ’s righteousness, you do not have the gospel or gospel unity (1 Cor. 1:17; 2 Cor. 5:21). The ECT initiative repeatedly avowed that the signatories had a unity of faith in the gospel. This included Roman Catholic signers who affirm the canons and decrees of the sixteenth-century Council of Trent, which anathematizes sola fide. I believe there are true and sincere Christians within the Roman Catholic and the Orthodox churches. But these people are Christians in spite of their church’s official doctrinal positions."
Mr. Sproul, I would like to make two observations. First, as you well know, in reference to the doctrine of justification, the only place in all of Scripture that the words "faith alone" are used, they are, to quote a video I once saw, "proceeded by the words NOT BY." Indeed, what would God have had to say in order to make you believe this? To this very simple truth could be added that St. Paul only ever teaches that a "faith working by love" (Gal. 5:6) is one that justifies, and that we are to "work out our own salvation with fear and trembling." (Phil. 2:12) Never unaided by grace, of course. That would be impossible. But works are necessary to justification and salvation. At the very least, even if over half of the world's Christians are wrong on these interpretations of Justification, you could at least be more charitable in your understanding of their biblical origin.
Your reply to that statement is likely to be something along the lines of "it's not charitable to allow someone to persist in error." Fair enough. But given the that these teachings have the weight of the Church and Tradition, plus the Scriptural references cited above (and many others I have not cited), perhaps you need to revisit whether or not Sola Fide is the central doctrine of Scripture, or even a Christian doctrine at all.
Secondly, this excerpt:
"At least one of the document’s framers, Mr. Colson, sees the Manhattan Declaration as a way to revitalize the church in America. In his commentary on November 25, Mr. Colson said the Manhattan Declaration is “a form of catechism for the foundational truths of the faith.” He suggests that the Manhattan Declaration is an antidote to “biblical and doctrinal ignorance” within the church. However, true reformation and revival within the church and the winning of our culture to Christ will come only through the power of the Holy Spirit and our clear, bold proclamation of the biblical gospel, not through joint ecumenical statements that equivocate on the most precious truths given to us."
That last statement is something with which I would strongly disagree. There are several reasons for this. First, Jesus prayed "that they may all be one...that the world may believe." (John 17) The gospel is more effective when there is unity. To say otherwise is to argue with Jesus. But secondly, and perhaps more importantly, is the idea that the three issuses tackled by the Manhattan Declaration (Sanctity of life, Marriage, and Religous liberty) are not integral to the gospel. While I am not an expert in anyway on the third, the first two of these issues I would like to briefly address. First, true love cannot take place outside the boundaries set by the Moral law, the ten commandments. For the summary of the law is to love God and love your neighbor. Since it is only faith that which works by love that can justify the sinner, dealing with what is perhaps the most gruesome manifestation of love's opposite, hatred, is indeed at the heart of the gospel.
Secondly, Mr. Sproul, even if you refuse to consider marriage a sacrament, you must admit that marriage is the grandest of the figures of redemption. Each man and woman that marries is participating in the love of Christ (the Bridegroom) and his Church (the Bride). The paradigm that is set up from the creation of Male and Female in the garden of Eden is that marriage is supposed to result in the creation of life. The marriage of Christ to his Church is a life-giving one. He sacrifices himself, and in death, gives us his life. Homosexuality, and all other forms of sexual infidelity, cannot function in the same way. Christian teaching on marriage is not simply meant as a set of rules to destroy the fun of pagans. It is protection of the fact, that our marriages are themselves the sign of God's life-giving love. Teaching against homosexuality is not something that is limited to a few select passages from Levitical law or St. Paul. It is the understanding that our view of redemption is, or at least should be, predicated on the figure of marriage: a groom who gives up and puts before his own interests that of his bride, who in return gives her whole self to him "for the life of the world." Indeed, defending marriage is not ancillary to the gospel, but is central to it.