Moreover, faith is twofold. For faith cometh by hearing. For by hearing the divine Scriptures we believe in the teaching of the Holy Spirit. The same is perfected by all the things enjoined by Christ, believing in work, cultivating piety, and doing the commands of Him Who restored us. For he that believeth not according to the tradition of the Catholic Church, or who hath intercourse with the devil through strange works, is an unbeliever.
But again, faith is the substance of things hoped for, the evidence of things not seen, or undoubting and unambiguous hope alike of what God hath promised us and of the good issue of our prayers. The first, therefore, belongs to our will, while the second is of the gifts of the Spirit.
Further, observe that by baptism we cut off all the covering which we have worn since birth, that is to say, sin, and become spiritual Israelites and God’s people.
Reproduced in full. Translation: Nicene and Post-Nicene Fathers, series 2, vol. 9 (Schaff and Wace, 1899), public domain (Public domain).