Paul says by inspiration in First Corinthians 1:17 to 2:16 that =mental= capacity, even of the highest excellence, when exercised by itself, is utterly incapable of apprehending spiritual truth in any degree whatever. And Christ says that it is with the =heart= that man believes unto righteousness. This defines that attitude of the whole personality which accepts the Word of God on faith without necessarily understanding it, and which gives evidence of acceptance by such a whole-hearted surrender to it as will eventuate in a life of righteousness. Then in other Scriptures we find that a life of righteousness, according to the divine standard, is based on right relations with God in Christ through faith in His shed blood, through whose incoming and indwelling life, in response to such a faith, the one who receives it will normally live in right relations with his fellow men. That is, it is a righteousness that is obtained by =believing=, not attained by =working=. It is received, not achieved. The use of the term "heart," therefore, in Scripture, means that certain attitude of the whole personality toward God through His Word which the exercise of the intellect apart from, and unfounded on, faith makes impossible. It is precisely this distinction in faculties that Christ's formula requires. For it was =spiritual= truth, not natural, of which He spoke when He said, "=If= any man wills to do, he shall =know=." To work by this formula requires the exercise of faith. For faith is that attitude of the heart toward the doing of God's will which is evidenced in =willing to do= that will, no matter what it costs nor where it leads. This is the first step of faith. For faith is both an attitude and an act, the genuineness of which is proven by an activity. That is, it is an attitude of willingness toward the will of God, an act of surrender to the will of God, eventuating in an activity in continuing in the will of God. Therefore complete surrender of the heart and life to God's will as revealed in the Word, trusting the outcome to Him, is where faith begins. And so let no man imagine that he has any real faith either in God or His Word who has not begun by willing to do, that he may enter upon the doing of, the will of God. Indeed, this is not simply the place where faith begins, it is also the only place where the presence of faith can be demonstrated. For this is the only possible way of distinguishing that intellectual attitude which simply assents to the truthfulness of the Word, from that genuine heart faith which actively reckons the Word to be true by surrendering the life to its requirements. This formula of Christ's, therefore, not only requires that the spiritual and natural faculties be distinguished, but it is the one scientific test by which they =can= be distinguished.