And, behold, Cushi came; and Cushi said, Tidings, my lord the king: for the LORD has avenged you this day of all them that rose up against you.
Read Chapter 18
Salvian the Presbyter
When his rebellious son chased him from his kingdom, the Lord soon delivered David. Not only did the Lord deliver him, but [he] delivered him more fully than the one delivered wished. This was that God might show that the injustice is more grievous to himself than to those who suffer it. He who avenges beyond the wish of him who is being avenged, what else does he want understood than that he himself is being avenged in him for whom he is doing the avenging? Thus, when, for his attempted patricide, David’s son being hanged on a cross not made by human hands, the Scripture says that the punishment, divinely brought on him, was thus announced: “I bring good tidings, my lord, the king: for the Lord has judged on your behalf this day from the hand of all that have risen up against you.”
You see how the Scriptures prove by divine witnesses that God judges not only by deeds and by examples, as I have already said, but does so today by the very name and terms of judgment. - "The Governance of God 2.3–4"