What does it say?
The events of chapters 18-20 summarize David’s wars and victories which was drawn from the content of 2 Samuel 8-21. The Chronicler also shows David as a king that ministered justice and righteousness for all his people. (vs. 18:14) The chronicler gives Satan credit for moving David to number Israel. (vs. 21:1) Joab did not agree with the census; therefore, he did not number the tribes of Benjamin or Levi. (vs. 21:6) The Lord was angry; therefore, he struck Israel but gave David a choice through the the prophet Gad, three things: three years of famine, three months of being swept by his foes, or three days of pestilence. David leaned on the graciousness of God and choose the three days of pestilence. This lead to David purchasing the threshing floor of Oran the Jebusite to build an alter on which David offered burnt offerings and peace offerings to the Lord. After this, the Lord withdrew from destroying Jerusalem with pestilence.
What does it mean?
The events of chapters 18-20 did not take place after the events of the ark of God being brought into Jerusalem or the Davidic covenant being given through the prophet Nathan. However, the Chronicler places them here to show the reader God’s providence. Even the events of chapter 21 show the providence of God. God uses evil for good. God allowed Satan to move David to number Israel which brought about the wrath of God. Before this incident occurred, the tabernacle of the Lord that Moses made, and the alter of burnt offerings was at the high place in Gibeon. Gibeon was a priestly city in the territory of Benjamin. David could not go there to offer sacrifice because of the pestilence occurring outside of the city. Therefore, he offered sacrifice at the location in Jerusalem that would later become the sight for the temple.
What shall I do?
I shall recognize that the Lord God is sovereign overall. Everything that occurs on the earth, occurs by the providence of God. The Lord is king of heaven and earth no matter what his enemies might think. God can use evil to bring about good. God used evil to bring about the purchase of the site that would be later used for the building of the temple in Jerusalem. Nothing that occurs on the earth happens under the radar of our God. The seed of David, who is the Son of God, who is Jesus Christ the Lord is on the thrown. He is the true Davidic king who administers justice and righteousness for all his people. He forever defeated Satan, sin and death at the cross. Christ died for our sins and was buried and rose again from the dead on the third day. (1 Corinthians 15:3-4) Now God can be just and justifier for all who believe in Jesus. (Romans 3:25)