The army divisions that were on duty month by month throughout the year

1 Chronicles 27:1-34
This is the list of the Israelites—heads of families, commanders of thousands and commanders of hundreds, and their officers, who served the king in all that concerned the army divisions that were on duty month by month throughout the year. Each division consisted of 24,000 men.
Officers of the Tribes.
The king's overseers.
Ahithophel was the king’s counselor. Hushai the Arkite was the king’s confidant. Ahithophel was succeeded by Jehoiada son of Benaiah and by Abiathar. Joab was the commander of the royal army.
All 12 army commanders seem to have come from David's special guard of 'mighty men'
The officers in charge of the tribes, those in charge of the king's property - storehouses, produce and livestock - and his personal advisers.
Why?
All of the management is organized by King David. 
To be a king of Israel have to organize his property and everything is normal and efficient. so using the right men to do the right thing is necessary to a good leader.
-------------------
23-26記載利未人在聖殿的事工安排。
這裏記載各支派有份於聖殿的建造。服事王，即王吩咐的工作，更有可能與聖殿有關的工作。管理府庫的人等等，都已經預備好了來建造的工作。教會的同工也是與教會的事工有關。正如教會弟兄姊妹，平日工作是教會工作的延伸。尤其在創啟地區，有基督徒在工作，讓當地人可以接觸到基督徒，認識這個信仰。
23節沒有數20歲以下的人。神為此生氣，所以沒有記載人數。因為神曾應許亞伯拉罕的後裔如天上的星、海邊的沙，是無法數的。大衛的舉動是把神限制住了，他沒有信心，妨礙的神的主權。後來還有許多人參與建造的工作。我們這人也是透過許多的的工作，來建造我們自己人的身上建造。
-------------------
How?
Serve the Lord is the same have to be in order and doing the right thing for God is my king. All of us are the servant of the Lord.