4. + the Work of Mary?
If I praised St. Paul for his prolific letter writing, tireless fight against the Judaizers, unquenchable desire to spread the Gospel, and legacy of church planting by saying “I don’t know where the Gospel would be without Paul” no one would bat an eye.
However, I can’t do anything like that with Mary. I could never utter “Without Mary there is no Incarnation.” I don’t dare bring up that if we all bore Christ into the world, proceeded with haste to be with others, cared for children in danger, sought out the lost, pondered the actions of God in our heart, meekly interceded on behalf of those who may not be aware of their need yet, stood by those suffering, and gathered with the Church in prayer (aka if we were more Marian) then Christianity would be richer and more vibrant. Saying any of that will likely mean I am accused of being a gospel denying, apostate, idolater. Now you may say, “I don’t have a problem with what you said, except when you make Mary necessary for salvation.” That raises a great question. Was Mary necessary for God to achieve our salvation? No. Did God, by choosing to take flesh through Mary, give her a necessary role in our salvation? Unequivocally, yes. It’s a lot like the Cross. Read this Socratic Dialogue  if you are confused.
5. + Prayer?
Many Protestants will be quick to point out that the Bible calls us all saints. Which is true, which makes their denial of the intercession of the saints strange. Denying the intercession of the saints as a violation of Christ’s mediation is to deny that any of us can pray on each other’s behalf. However, interceding on behalf of one another, even loving someone to express God’s love for him/her (you could call that mediation) does not violate Christ’s singular role as the mediator of the New Covenant between heaven and earth, God and humanity. Catholics are no different from Protestants in believing that we can and should pray for one another. However, we differ because Catholics believe that those standing face-to-face with the Lord and Lover of Souls can pray for us. They pray in and through Christ. Their prayer like mine or yours, not Christ’s unique mediation from the altar of the cross. And once again, the Protestant obsession with only/sola statements butts up against the Trinity as it is very clear in Scripture that the Holy Spirit intercedes on our behalf (cf. Rom. 8:26-27). I bring this up because the Protestant proof text against a Catholic understanding of the intercession of the saints is 1 Tim. 2:5, in which Paul specifically emphasizes Christ’s incarnation, His humanity, as the linchpin of His unique mediation. The point being, that the common Protestant apologetic regarding this passage proves too much as it was not the Spirit that became incarnate.
6. + Tradition?
Did you know the reformed theology that seems to have saved the Gospel from the shackles of Catholicism is a tradition? Did you know the Table of Contents in the front of your Bible is a tradition? Did you know the Bible is in fact written tradition? And in written tradition we find the command to observe all that was passed down by letter and word of mouth.  Weird…
“[Christ] is himself both the mediator and the sum total of Revelation” (Dei Verbum, 2).
7. + Response?
Why does free gift equal no response in reformed theology but nowhere else in God’s universe? My life is a free gift… guess I don’t need to breathe. In all seriousness, Catholic theology talks about response, Challies though decides to articulate it as effort possibly to emphasize his accusation of a works doctrine. More about this in # 9. (Read Bonhoeffer’s chapter in The Cost of Discipleship on “Single-Minded Obedience” to really see an honest wrestling with the need for response from a very faith-filled Protestant Christian) .
8. + The Mass?
The Mass is not added to the Cross. It is the door to the Cross. Check out The Lamb’s Supper, Jesus and the Jewish Roots of the Eucharist, The Mass of the Early Christians, or The Fourth Cup. Seriously, I’ll buy it for you. (Here is my email: firstname.lastname@example.org)
16. What do Catholic’s believe about the transmission of that “faith that was once for all handed down (traditio) to the holy ones” (Jude 1:3)? Find out in Dei Verbum (On Divine Revelation) from Vatican II.
17. “Single-Minded Obedience,” 79-85.