Image via Wikipedia"But faith, which the Greeks disparage and regard as useless and barbarous, is a voluntary preconception, the assent of piety; “the substance of things hoped for, the evidence of those things which are’ not seen,” according to the divine Apostle. “For by it most especially did the men of old have testimony borne to them; and without faith it is impossible to be pleasing to God. Others, however have defined faith as an intellectual assent to a thing unseen, since certainly the proof of a thing unknown is manifest assent. … He, then, that believes Scriptures with firm judgment, receives, in the voice of God, who gave the Scriptures, an unquestionable proof. Nor by proof does faith become more firm. Blessed, therefore. are those who have not seen and yet have believed."
St Clement of Alexandria, The Instructor of Children