Men in a natural condition may have convictions of the guilt that lies upon them and of the anger of God and their danger of divine vengeance. Such convictions are from the light of truth. That some sinners have a greater conviction of their guilt and misery than others is because some have more light, or more of an apprehension of truth, than others. And this light and conviction may be from the Spirit of God. The Spirit convinces men of sin, but yet nature is much more concerned in it than in the communication of that spiritual and divine light. It is from the Spirit of God only as assisting natural principles, and not as infusing any new principles. Common grace differs from special in that it influences only by assisting of nature, and not by imparting grace or bestowing anything above nature. The light that is obtained is wholly natural, or of no superior kind to what mere nature attains to, though more of that kind is obtained than would be obtained if men were left wholly to themselves. Or, in other words, common grace only assists the faculties of the soul to do more fully what they do by nature, as natural conscience or reason will by mere nature make a man sensible of guilt and will accuse and condemn him when he has done amiss. Conscience is a principle natural to men, and the work that it does naturally, or of itself, is to give an apprehension of right and wrong and to suggest to the mind the relation that there is between right and wrong, and a retribution. The Spirit of God, in those convictions that unregenerate men sometimes have, assists conscience to do this work in a further degree than it would do if they were left to themselves.

From “A Divine and Supernatural Light,” p. 13