According to traditional Christian understanding, the author of 2 Chronicles shows that the king hired strong soldiers because he wanted to win a battle, even though he was supposed to trust God more than money. It teaches us that relying on God is more important than using our own ways to solve problems.
2 Chronicles 25:6: He hired also an hundred thousand mighty men of valour out of Israel for an hundred talents of silver.
This verse contradicts 2 Chronicles 25:6 as it warns not to go with Israel in battle, stating that God is not with Israel, while 25:6 details hiring Israelites as soldiers.
2 Chronicles 25:8: But if thou wilt go, do [it], be strong for the battle: God shall make thee fall before the enemy: for God hath power to help, and to cast down.