He who believeth then the divine Scriptures with sure judgment, receives in the voice of God, who bestowed the Scripture, a demonstration that cannot be impugned. Faith, then, is not established by demonstration. "Blessed therefore those who, not having seen, yet have believed." ...Now the followers of Basilides regard faith as natural, as they also refer it to choice, [representing it] as finding ideas by intellectual comprehension without demonstration; while the followers of Valentinus assign faith to us, the simple, but will have it that knowledge springs up in their own selves (who are saved by nature) through the advantage of a germ of superior excellence, saying that it is as far removed from faith as the spiritual is from the animal. Further, the followers of Basilides say that faith as well as choice is proper according to every interval; and that in consequence of the supramundane selection mundane faith accompanies all nature, and that the free gift of faith is comformable to the hope of each. Faith, then, is no longer the direct result of free choice, if it is a natural advantage.
Source: The Stromata Book 2