Romans 14:23

But he that doubteth is condemned if he eat, because he eateth not of faith; and whatsoever is not of faith is sin. [The apostle here presents the contrast between the strong and the weak. The former is blest indeed in that he has liberty without the sense of inward disapproval, while the other, not sure of his ground, plunges recklessly on, and, acting contrary to his convictions, and hence to that respect and reverence which is due to God, sins. His eating is sinful because not of faith (faith is here used in the abstract sense, and means grounded, undoubting conviction that God approves), for whatever is done without such settled conviction is sinful recklessness, and must not be done at all, for to act contrary to the will of God is to destroy his work in us. Diakrenesthai, translated "doubteth," means to be divided into two persons, one of whom says "yes," and the other "no." In the case of the weak the flesh says "yes," and conscience cries "no."]