https://www.btstories.com/numbering-the-people/

King David called for Joab and said, “Go throughout the land and number all the people.” He did this to see how big of an army he could build.

Joab knew this wasn’t God’s will for David. He said, “Don’t disobey the Lord. God will give you as many people as you need for any situation.” But David insisted, so Joab used his army to go to every part of Israel and count the people. When they were finished, he told David there were over 1,300,000 men who were able to go to war if needed.