1 Chronicles 12:38, commentary and pictures

Capable, loyal men of war from the different tribes came with a perfect heart to Hebron to make David king over all Israel, and all the rest of Israel were of one heart to make him king. The men who came were united in purpose and wholehearted in support, able to keep rank and not divided in heart. The assembly at Hebron involved 350,000 fighting men and lasted three days as a festival.

Coming with a perfect heart means coming with wholehearted, undivided purpose and support, and keeping rank goes with that heart. That heart is a gift from God that gives both the disposition and the ability to keep rank and to work loyally together in fellowship. The gathering is a lesson in organization, for with that heart they all knew what Israel ought to do at that critical time. They were subject to one another and chose earnest leaders to secure harmonious action so that every man's work counted for the most, together becoming a great host like the host of God under leaders with whom David consulted.

For workers serving God, unity and steadfastness in keeping rank depend on wholehearted commitment. Divided interests cause breaking rank, while a perfect heart guards against distractions that draw workers away from the work to which God has called them. Thousands of workers with such hearts should keep rank as they serve together, including in spreading literature containing God's truth.