Why a change cannot be done without, and why the Lord should fulfill his promise, "I will give them one heart and I will put a new spirit within you; and I will take away the stony heart out of their flesh, and will give them an heart of flesh" (Ezek. 11:19) is not understood. But I will endeavor to show you why it is necessary.
Man, in consequence of sin, is at enmity with God. He desires not the knowledge of God, nor does he wish to walk in his ways. The apostle declares, that "the carnal mind is enmity against God, for it is not subject to the law of God: neither indeed can be." (Rom. 8:7) God and the unpardoned sinner have no tastes nor interests in common. They are as opposite the one to the other as light and darkness, as heaven and hell!
Supposing a man had broken the laws of the land, or that he had been a traitor to his Sovereign; but that he were still allowed to be a free man. As yet no action had been taken against him, although he was in daily expectation of being placed in custody, and brought to trial. Would this man be at ease, or presuming he was by some means thrown in the way of royalty, would he, under the circumstances, be happy? On the contrary, if the man had been tried, found guilty, and condemned; and, if when just upon the eve of being executed, the monarch had sent a special messenger to the governor of the jail to say, not only that the culprit was not to be executed, but that he was to be clad in the royal garments which had been forwarded for his special use, and that he was to be sent with all possible haste to the palace, into which he was henceforward to be received as one of its lawful guests; how would that man feel under these completely altered circumstances?
Would there not be love, and admiration, and the utmost possible attachment to his Sovereign, in the place of the hatred and plotting against the person and interests of the Sovereign? Would there be an atom of traitorism and treachery remaining in that man's heart? Would anything satisfy this man in regard to the debt of gratitude he owed, and the amount of homage and obedience he wished to render? Would there be so loyal a subject in the whole of that monarch's dominions as that pardoned rebel?
Now, this is a key to the true ground for love to God, and the prospect of being truly happy in heaven. It is not the mere escape from hell, it is not simply being freed from condemnation and wrath to come; but it is the realization of what the Lord himself is, what he himself has done for poor sinners who had rebelled against him, and respecting whom they had said, "Who is the Lord, that I should obey his voice?" (Exo. 5:2) And "We will not have this man to reign over us." (Luke 19:14)