"Satan rose up against Israel and incited David to take a census of Israel" (1 Chron 21:1-2).
God always requires total trust in Him alone for our victories in life. Throughout scripture we are cautioned not to place our trust in the strength of horses, other men or our own abilities. David's decision to take a census was a failure to keep his trust totally upon the Lord.
David's purpose in counting his population was to assess his military strength, much like the second census taken under Moses (Num. 1:2,3). David found 800,000 men eligible for military service in Israel and 500,000 men in Judah (2 Sam. 24:9), more than double the previous head count.
David's commander evidently recognized the grave error that his king was about to make. "But Joab replied, 'May the LORD multiply his troops a hundred times over. My lord the king, are they not all my lord's subjects? Why does my lord want to do this? Why should he bring guilt on Israel?'" (1 Chron 21:3).
This census displeased the Lord. David was falling into the temptation of trusting in the size of his army rather than in the Lord. God punished David and reduced his forces by bringing a plague that killed 70,000 men (1 Chron 24:14,15). How do we do this in our lives today? We trust our bank accounts, our skills, and the security of our workplace. When we begin placing our faith in these things instead of the provider of these things we get into trouble with God.
What a lesson this is for each of us. Today, place your total trust in the Lord for all of your needs.