(Read 2 Samuel 24:10-15)
It is well, when a man has sinned, if he has a heart within to smite him for it. If we confess our sins, we may pray in faith that God would forgive them, and take away, by pardoning mercy, that sin which we cast away by sincere repentance. What we make the matter of our pride, it is just in God to take from us, or make bitter to us, and make it our punishment. This must be such a punishment as the people have a large share in, for though it was David’s sin that opened the sluice, the sins of the people all contributed to the flood. In this difficulty, David chose a judgment which came immediately from God, whose mercies he knew to be very great, rather than from men, who would have triumphed in the miseries of Israel, and have been thereby hardened in their idolatry. He chose the pestilence; he and his family would be as much exposed to it as the poorest Israelite; and he would continue for a shorter time under the Divine rebuke, however severe it was. The rapid destruction by the pestilence shows how easily God can bring down the proudest sinners, and how much we owe daily to the Divine patience.
For a more detailed summary select the link below.
2 Samuel 24 Bible Commentary – Matthew Henry (concise) (christianity.com)
2 Samuel 24:10
10 David’s heart struck him after he had counted the people. David said to Yahweh, “I have sinned greatly in that which I have done. But now, Yahweh, put away, I beg you, the iniquity of your servant; for I have done very foolishly.”