David was given the position of king long before he was able to actually sit on the throne. King Saul before him had lost the leadership role, but rather than give it up, he repeatedly tried to kill David.
Besides that, other enemies tried to kill David. The Philistines wanted him dead. Rebels of his own people wanted him dead. He was largely popular, but even popular people are hated by some and David had to be on guard all the time.
The Old Testament battles, David’s and others, were real physical battles of various sizes and for various reasons. People died. Territories were taken. Women and children suffered. I don’t understand all of the reasons why God told His people to rage war against their pagan enemies, but I do know that the physical battles in those days serve as patterns for the spiritual battles God’s people fight now.
Some Christians think that the followers of Jesus should be pacifists. Many struggle with the Old Testament wars and wonder if this was even the same God as the one revealed in the New Testament. Maybe I oversimplify, but in my mind, God hates evil. This was expressed differently before and after Jesus came, but He never changes; He still hates evil.
Because of this, when I read verses about enemies and battle from the Old Testament, I think about the spiritual battles that I fight. Some of them are against the evil and sin in my own heart. I am forgiven and have new life, but that old nature still tries to overrule all the good that God has done in my life. To win this battle, I need to stop fighting God and obey Him.
Some of my battles are against forces outside of me. For sure, Satan is the big enemy. He is subtle with his lies as he attempts to corrupt the truth about God and the way I should live. He even goes at me physically and mentally. To make him flee, I need to resist his tactics. I also need to constantly focus on the truth.
A third arena is enemies with skin on, people who hate God, hate the gospel, and want to discredit everything that Christianity believes in and stands for. While the big enemy is behind their actions (they have fallen for his lies), these people are willing participants in what is called persecution. For these battles, I need to pay careful attention to God. Each situation is different. Only He can tell me what to do.
If I lived in OT times, God might send me into hand to hand combat with such people. However, Jesus’ tactics are usually not like that. For some, He may ask me for verbal responses. For others, it is a simple, “Be still and know that I am God” (Psalm 46:10).
As I walk with Him, I can vouch for the words of King David in this psalm, “Blessed be the Lord my Rock, Who trains my hands for war, and my fingers for battle” (Psalm 144:1). I must add that He also trains my mouth to both speak and be quiet, my feet to both stand firm or just walk away, and above all, He teaches my heart to listen to what He says and to trust Him with the outcome.