Trust in the Lord almighty

1 Chronicle 21:1-17
Satan rose up against Israel and incited David to take a census of Israel.
In all Israel there were one million one hundred thousand men who could handled  sword, including four hundred and seventy thousand in Judah.
But Joab did not include Levi and Benjamin in the numbering, because the king's command was repulsive to him.
This command was also evil in the sight of God; so he punished Israel.
David chose the one : let him fall into the hands of the Lord, for his mercy is very great; but do not let him fall into the hands of men.
Why?
For the Chronicler the census and plague are significant simply as the lead-in to David's decision to build the Temple on the site of Ornan's threshing-floor, a fact not even mentioned in Samuel.
2 Samuel has 'God', It is God who sets the limits to Satan's power. His existence in God's world, and the reason why God allow him power to act, remain a mystery.
Joab did not number Levi and Benjamin, Levi is the servant of the Temple, Banjamin is the tribe of Saul.
David chose the one fall into hands of God instead of fall into hands of men. This is right decision. For Gos is full of mercy.
How?
Something we don't understand the plan of God, but trust in God for he always loves us and his mind is always beyond us.