Often, Protestants will abuse biblical and patristic texts to support Sola Fide, such as 1 Clement. However, an author or text extolling "faith" or even the term "faith alone" is not enough to justify (pun intended) the Protestant reading of such texts. The following "checklist" is what an author/text must teach to support a Sola Fide reading of a passage:
Sola Fide "Checklist" (taken from Perry Robinson [EO])
Defining Sola Fide
Created Righteousness
Faith an empty/worthless virtue
Instrumental extrinsic cause
Conduit of Justification
Forensic/Taxonomic Reclassification (Nominalist)
Transfer of Created Merit
Separation of Activities
Zero Sum
Quantitative
No Merit simpliciter
The above comes from his lengthy (5 hours!) refutation of Anthony Rogers (Reformed):
AN ORTHODOX RESPONSE TO ANTHONY ROGERS: THE CHURCH FATHERS AND SOLA FIDE
Further Reading
An Examination and Critique of the Theological Presuppositions Underlying Reformed Theology
Response to a Recent Attempt to Defend Imputed Righteousness