A few days ago, I wrote an article regarding the observation of a Catholic friend, far advanced beyond me in years, who is seemingly frantically doing "good works" in order that he might be saved, or perhaps saved from purgatory.
Another dear Catholic friend made earnest comments to defend this behavior, in the comments of that post, to which I thought I would bring forth Dr. John Piper's defense of Justification by faith, and faith alone.
Here is Dr. John Piper's most recent sermon, working his way through the Book of John. You will find his discussion of Justification at the 38:00 marker. However, I highly recommend listening to the whole discourse on the resurrection of the dead.
Another interesting set of videos, on the disparity of understanding of Justification, was brought forth by my friend Barbara.