Numbers are important throughout scripture

• 5000 fed and sit by 50s
• 276 in the ship that wrecked

Why was this wrong for David?

• 1Chron 27: 23-24? No, this is not the parallel to 2Sam 24
• Abrahamic Covenant? Descendants would be innumerable

The real fault on David's part was pride.
1Chron 21:2 comes right after 1Chron 20 - the wars against the giants of the Philistines; and so David felt the need to count to see how powerful he and his army was.

1Chron 21:3  "why will he be a cause of trespass to Israel?" Joab, while not usually great to trust, was right in this.

1Chron 21:5 -- 1,100,000 and 470,000
2Sam 24:9 -- 800,000 and 500,000
Same census but different numbers; an error? Take into account the soldiers who were already defending

2Sam 24:10 David realized he had sinned and asked for forgiveness
2Sam 24:11-14 David chose

2Sam 24:1 The Lord
1Chron 21:1 Satan

Numbers 22:22; 1King 11:14 in these verses the same word is used as in 1Chron 21:1 and means adversary. God placed David in an adversarial situation.