"Satan rose up against Israel and caused David to take a census of the people of Israel." -1 Chronicles 21:1
In the Old Testament, David instructed Joab, the commander of the army, to take a census. This may not ordinarily have been a noteworthy event, except for the fact that David suffered enormous consequences by taking this census. God gave David a choice of three punishments: three years of famine throughout Israel, three months of fleeing from his enemies, or three days of severe plague. (2 Samuel 24:12) Ouch!
Influenced by Satan, David sinned by counting the people. In Moses' time, God gave instructions that if a census were to be taken, an offering had to be collected.
"Then the Lord said to Moses, 'Whenever you take a census of the people of Israel, each man who is counted must pay a ransom for himself to the Lord. Then no plague will strike the people as you count them. Each person who is counted must give a small piece of silver as a sacred offering to the Lord. (This payment is half a shekel, based on the sanctuary shekel, which equals twenty gerahs.)'" -Exodus 30:11-13
But it was David's disobedience that caused the plague. He was trusting in numbers instead of in God. The people were not his - they were God's.
It's great to have a budget, a schedule, or a way to organize or record what we're doing. But when these types of details supersede our faith and trust in God, or we find confidence in our resources instead of in Him, we can set ourselves up for failure.
Do you place your trust in God, even in the small things? God knows what we need. Allow Him to take any area you may struggle in and give it all to Him. He knows the answer to everything we need.