1 Chronicles

But prosperity exposes David to the temptations of the enemy. Head over Israel, and conqueror of all his enemies, he wishes to know the strength of Israel, which was his glory, forgetting the strength of God, who had given him all this and had multiplied Israel. This sin, always a great one and still more so in David's case, did not fail to bring chastisement from God — a chastisement however, which was the occasion of a fresh development of His grace, and of the accomplishment of His purposes. David, in his heart, knew God although for a moment he had forgotten Him, and He commits himself to Him, choosing rather to fall into the hands of God than to hope anything from man; and the pestilence is sent by God. This, by the grace of God, gives occasion for another element of David's glory — for the honour which God gave him of being the instrument to fix the spot, where the altar of God was to be the means of the daily connection between the people and Himself. Jerusalem was beloved of God. This election on His part is now manifested. The spot of ground in question was the threshing-floor of a stranger; the moment was one in which the people were suffering under the consequences of sin. But here all is grace; and God stays the angel's hand when stretched out to smite Jerusalem. Grace anticipates all movement in David's heart;* for it acts and has its source in the heart of God. Moved by this same grace, David on his part intercedes for the people, taking the sin on himself; and God hears his prayer, and sends His prophet to direct him in offering the atoning victim, which in fact formed the foundation of all subsequent relationship between the people and God. One cannot but feel — defective as the type is,** in comparison with the reality — how much this calls Him to mind who took upon Himself, and even in behalf of this very people, the sin which was not His own.
{* It is interesting to see the order unfolded here in the establishment of the relations of sovereign grace: first of all, the heart of God and His sovereign grace in election, suspending the execution of the deserved and pronounced judgment (ver. 15); next, the revelation of this judgment, a revelation which produces humiliation before God and a full confession of sin before His face. David, and the elders of Israel, clothed in sackcloth, fall upon their faces, and David presents himself as the guilty one. Then, instruction comes from God, as to that which must be done to cause the pestilence judicially and definitively to cease, namely, the sacrifice in Ornan's threshing-floor. God accepts the sacrifice, sending fire to consume it, and then He commands the angel to sheathe his sword. And sovereign grace, thus carried out in righteousness through sacrifice, becomes the means of Israel's approach to their God, and establishes the place of their access to Him. The tabernacle, a testimony to the conditions under which the people had failed, offered, as we have seen, no resource in such a case. On the contrary, it occasioned fear. He was afraid to go to Gibeon. Nothing would do but the definitive intervention of God according to His own grace (the circumstance of the sin, on the king's own part, leaving no room for any other means). The whole system and principle of the tabernacle as a legal institution is set aside, and the worship of Israel founded on grace, by sacrifice coming in where all, even the king as responsible, had failed. Such was Israel's position for him who understood it.
** And even historically quite opposed; for it is the king's own sin that has brought chastisement on the people. Christ, however, made the sin His own. Nevertheless, this shews us how everything depended now on the throne. It is not the priest who brings in the remedy. David intercedes and David offers. The fact that the king, in whom the promises were, had sinned, made sovereign grace necessary.}

David having offered the sacrifice according to God's ordinance, God marks His acceptance of it by sending fire from heaven; and at God's command the angel sheathes his sword.

Here all is evidently grace. It is not the kingly power which interposes to deliver Israel from their enemies, and gives them rest. The ark of the covenant being there through the energy of faith, out of its regular place which is now desolate in consequence of the people's sin, it is Israel's own sin* (for all depends upon the king) which is in question. God acts in grace, ordains and accepts the atoning sacrifice; David, in sackcloth with his elders, presenting himself before Him in intercession.
{* This difference between Israel's deliverance from their enemies, and the sense of their own sin before God, in the last day, is found in the psalms of degrees: see Psalm 130.}

In the place where God has heard his prayer, David offers his sacrifices; and of this place it is said, "This is the house of Jehovah-Elohim, and this is the altar of the burnt-offering for Israel." In the presence of the sin, God acts in grace, and institutes, by means of sacrifice, the regular order of the religious relationship between Himself and His people who are accepted in grace, and the place of His own habitation in which they were to draw nigh unto Him.* It was a new order of things. The former presented no resource against the judgment of God: on the contrary, David himself feared to go to the tabernacle; it was all over with it as a means of approach to God. David's sin became the occasion of putting an end to it, by shewing the impossibility of using it in such a case, and by being thus made the occasion of founding everything upon sovereign grace.
{*Observe too here, how sin gives occasion to the bringing out of the counsels of God, though the responsibility was also met in what did so. So the cross. Compare Titus 1:2-3, and 2 Timothy 1:9-10; Ephesians 3; Colossians 1.}