From Abraham sacrificing Isaac, to Rahab the prostitute giving aid to God's people, and many other examples from both the old and new testament, God has never justified people by "faith only". "Faith only" is simply a catch cry coined by protestants in order to separate itself from the works-based doctrines, which do emphasis our own works more than our faith. The "saved by faith alone" catch cry is then important to reinforce that we are not saved by works of our own doing, but by faith. However it is not strictly accurate as a general statement of how people are justified.
We are saved by faith alone (meaning not of our own works) but the faith which saves is never alone (i.e. faith produces works, and in this context, these works arising from our faith do justify us before God). Yet, while works go with our faith, people are saved the moment they believe God's promises. What sort of works show our faith and justify us before God? Easy..prayer, studying God's word, the confession of our mouth, what we do with our daily life, are we good parents or good children, are we good servants or good leaders or good ministers etc, the sorts of things most people accept prove that a person is a christian. The sort of heart-faith which does result in a person acting differently to what they would otherwise.