Suppose a human sovereign should establish a government, and propose as the great end of pursuit, to produce the greatest amount of happiness possible within his kingdom. He enacts wise and benevolent laws, calculated to promote this object to which he conforms all his own conduct; in the administration of which, he employs all his wisdom and energies, and requires all his subjects to sympathize with him; to aim at the same object; to be governed by the same principles; to aim supremely and constantly at the same end; the promotion of the highest interests of the community. Suppose these laws to be so framed, that universal obedience would necessarily result in universal happiness. Now suppose that one individual, after a season of obedience and devotion to the interest of the government and the glory of his sovereign, should be induced to withdraw his influence and energies from promoting the public good, and set up for himself; suppose him to say, I will no longer be governed by the principles of good will to the community, and find my own happiness in promoting the public interest; but will aim at promoting my own happiness and glory, in my own way, and let the sovereign and the subjects take care for themselves. "Charity begins at home." Now suppose him thus to set up for himself; to propose his own happiness and aggrandizement as the supreme object of his pursuit, and should not hesitate to trample upon the laws and encroach upon the rights, both of his sovereign and the subjects, wherever those laws or rights lay in the way of the accomplishment of his designs. It is easy to see, that he has become a rebel; has changed his heart, and consequently his conduct; has set up an interest not only separate from but opposed to the interest of his rightful sovereign. He has changed his heart from good to bad; from being an obedient subject he has become a rebel; from obeying his sovereign, he has set up an independent sovereignty; from trying to influence all men to obey the government, from seeking supremely the prosperity and the glory of his sovereign, he becomes himself a little sovereign; and as Absalom caught the men of Israel and kissed them, and thus stole away their hearts; so he now endeavors to engross the affections, to enlist the sympathies, to command the respect and obedience of all around him. Now what would constitute a change of heart in this man towards his sovereign? I answer, for him to go back, to change his mind in regard to the supreme object of pursuit;--to prefer the glory of his sovereign and the good of the public to his own separate interest, would constitute a change of heart.
Now this is the case with the sinner; God has established a government, and proposed by the exhibition of his own character, to produce the greatest practicable amount of happiness in the universe. He has enacted laws wisely calculated to promote this object, to which he conforms all his own conduct, and to which he requires all his subjects perfectly and undeviatingly to conform theirs. After a season of obedience, Adam changed his heart, and set up for himself. So with every sinner, although he does not first obey, as Adam did; yet his wicked heart consists in setting up his own interest in opposition to the interest and government of God. In aiming to promote his own private happiness, in a way that is opposed to the general good. Self-gratification becomes the law to which he conforms his conduct. It is that minding of the flesh, which is enmity against God. A change of heart, therefore, is to prefer a different end. To prefer supremely the glory of God and the public good, to the promotion of his own interest; and whenever this preference is changed, we see of course a corresponding change of conduct. If a man change sides in politics, you will see him meeting with those that entertain the same views and feelings with himself; devising plans and using his influence to elect the candidate which he has now chosen. He has new political friends on the one side, and new political enemies on the other. So with a sinner; if his heart is changed, you will see that Christians become his friends--Christ his candidate. He aims at honoring him and promoting his interest in all his ways. Before, the language of his conduct was, "Let Satan govern the world." Now, the language of his heart and of his life is, "Let Christ rule King of nations, as he is King of saints." Before, his conduct said, "O Satan, let thy kingdom come, and let thy will be done." Now, his heart, his life, his lips cry out, "O Jesus, let thy kingdom come, let thy will be done on earth as it is in heaven."
In proof that the change which I have described constitutes a change of heart, if any proof is necessary--I observe, first, that he who actually does prefer the glory of God, and the interest of his kingdom, to his own selfish interest, is a Christian; and that he who actually prefers his own selfish interest to the glory of God, is an impenitent sinner.
The fundamental difference lies in this ruling preference, this fountain, this heart, out of which flows their emotions, their affections, and actions. As the difference between them consists not in the substance of their minds or bodies, but in the voluntary state of mind in which they are, it is just as unphilosophical, absurd, and unnecessary, to suppose that a physical or constitutional change has taken place in him who has the new heart, as to infer, that because a man has changed his politics, therefore his nature is changed. Further, this new preference needs only to become deep and energetic enough in its influence, to stamp the perfection of heaven upon the whole character. From long cherished habits of sin, and acting under the dominion of an opposite preference, when it comes really to be changed, it is often weak and measurably inefficient; and consequently the mind often acts in inconsistency with this general preference. Accordingly, God says to Israel, "How weak is thine heart!" Like a man who is so little under the influence either of principle or of affection for his wife, that although upon the whole, and in general, he prefers her to any other woman, yet he may occasionally be guilty of an act of infidelity to her. Now what is needed in the case of a Christian is, that his old habits of thought, and feeling, and action, should be broken up; that his new preference should gain strength, stability, firmness, and perpetuity; and thus take the control of the whole man. This process constitutes sanctification. Every act of obedience to God strengthens this preference, and renders future obedience more natural. The perfect control of this preference over all the moral movements of the mind, brings a man back to where Adam was previous to the fall, and constitutes perfect holiness.
Once more--If a change of heart was physical, or a change in the constitution of the mind, it would have no moral character. The change, to have moral character, must be voluntary. To constitute a change of heart, it must not only be voluntary, but must be a change in the governing preference of the mind. It must be a change in regard to the supreme object of pursuit.
Finally, it is a fact in the experience of every Christian, that the change through which he has passed is nothing else than that which I have described. In speaking from experience, he can say, Whereas I once preferred my own separate interest to the glory of my Maker, now I prefer his glory and the interests of his kingdom, and consecrate all my powers to the promotion of them forever.