Hence, that regeneration of which our Lord speaks in his discourse with Nicodemus is not a radical change of the conscience, but of the will and affections. We have already seen that the conscience cannot undergo a radical change. It can never be made to approve what it once condemned, and to condemn what it once approved. It is the stationary legislative faculty, and is, of necessity, always upon the side of law and of God. Hence, the apostle Paul sought to commend the truth which he preached, to every man’s conscience, knowing that every man’s conscience was with him. The conscience, therefore, does not need to be converted, that is to say, made opposite to what it is. It is indeed greatly stimulated, and rendered vastly more energetic, by the regeneration of the heart; but this is not radically to alter it. This is to develop and educate the conscience; and when holiness is implanted in the will and affections, by the grace of the Spirit, we find that both the conscience and understanding are wonderfully unfolded and strengthened. But they undergo no revolution or conversion. The judgments of the conscience are the same after regeneration, that they were before; only more positive and emphatic. The convictions of the understanding continue, as before, to be upon the side of truth; only they are more clear and powerful.
The radical change, therefore, must be wrought in the heart and will. These are capable of revolutions and radical changes. They can apostatise in Adam, and be regenerated in Christ. They are not immovably fixed and settled, by their constitutional structure, in only one way. They have once turned from holiness to sin; and now they must be turned back again from sin to holiness. They must become exactly contrary to what they now are. The heart must love what it now hates, and must hate what it now loves. The will must incline to what it now disinclines, and disincline to what it now inclines. But this is a radical change, a total change, an entire revolution. If any man be in Christ Jesus, he is a new creature, in his will and affections, in his inclination and disposition. While, therefore, the conscience must continue to give the same old everlasting testimony as before, and never reverse its judgments in the least, the affections and will, the pliant, elastic, plastic part of man, the seat of vitality, of emotion, the seat of character, the fountain out of which proceed the evil thoughts or the good thoughts,—this executive, emotive, responsible part of man, must be reversed, converted, radically changed into its own contrary.