Calvin says in his Institutes that “the knowledge of faith consists in assurance rather than in comprehension.” Faith, of course, must also comprehend, for it is not a blind faith that we have. What Calvin means, is that faith grasps that which cannot be seen. He says in the same section that, “faith is so far above sense that man’s mind has to go beyond and rise above itself in order to attain it. Even where the mind has attained, it does not comprehend what it feels.” He uses Paul in Ephesians 3:18, 19 to say that faith “is the power to comprehend…what is the breadth and length… and to know the love of Christ which surpasses knowledge”. This knowledge, he says, is lofty and we are “more strengthened by the persuasion of divine truth than instructed by rational proof.” We thus, acknowledge that we walk by faith and not by sight (2 Cor. 5:6, 7), and in this we are assured. (See Institutes III.2.14)