There are 5 fundamental biblical points that justbyfaith, Behold, Taken, and their ilk continually duck:
(1) I repeat: in both Hebrew ("amunah") and Greek (("Pistis") the word translated "faith" also means faithfulness." That in itself means that we are saved not by an act of belief or trust, but by a new way of being--or, as Paul puts it, by becoming "a new creation in Christ Jesus (2 Cor. 5:17)."
(2) Catholics can agree that, rightly understood, we are saved by grace alone in the sense that good works can't merit our salvation apart from grace. Put differently, our Fundamentalist posters don't get the philosophical distinction between necessary and sufficient conditions. Good works are a necessary condition for salvation (See e. g. James 2:14), but not a sufficient condition; we still need faith and grace. It is precisely because James teaches the essential role of works that Luther dismissed James as "an epistle of straw," whereas Catholics continued to view it as God's Word.
(3) The word "Catholic" (universal) became the first-century designation of the global church when the faith spread far enough after the apostolic age to become meaningfully universal throughout the Mediterranean world. The issue is not the Church's name, but that the clarification of basic doctrines took centuries. The term "Catholic" was also used to distinguish the widespread doctrinal consensus from local heresies like various forms of Gnosticism.
(4) Fundamentalists here act as if the Holy Spirit deserted the world right after the apostolic age. What they forget is this: If we can't trust the Holy Spirit to guide early Catholic tradition, then we can trust neither the doctrine of the limited NT canon nor the the doctrine of the Trinity. The Personhood of the 3 members of the Godhood is not explicitly taught in Scripture and is instead rightly inferred by later Catholic councils.
(5) The Bible may be inspired and authoritative, but it is NOT a book of systematic theology; indeed, it is woefully incomplete in its progressive revelation, leaving many important questions (e. g. abortion) without an explicit answer. So Catholic tradition and the gifts of the Spirit were necessary to develop new doctrines that are consistent with Scripture without being explicitly taught by Scripture. This is not to deny that our Bible still provides the basics for faith and life.