“But you will not even need to fight. Take your positions; then stand still and watch the Lord’s victory. He is with you, O people of Judah and Jerusalem . Do not be afraid or discouraged. Go out there tomorrow, for the Lord is with you!” 2 Chronicles 20:17 (NLT)
In today’s passage, God is talking to King Jehoshaphat and the Israelites. They’re about to be attacked by three enemies: the Moabites, the Ammonites, and the Meunites. 
Jehoshaphat had to be worried about how his people could defend themselves in such a battle, but God knew exactly what Jehoshaphat was thinking. He said, “You will not have to fight in this battle.” Now, that’s the kind of battle I like! 
What God tells Jehoshaphat in this passage, and what he would remind us today, is this: “The battle is not yours; it’s mine. You don’t have to fight in it.” In other words, it’s God’s problem. Let him solve it. The fact is if you are God’s child, then your problems are his problems. And he’s much better at fighting your battles and solving your problems than you will ever be. Your job is to trust him to work it all out. Perhaps the reason we have so many tired, fatigued, and discouraged Christians is because we think, “It all depends on me.”
The day you resign as General Manager of the Universe, you’re going to find that it doesn’t fall apart. You can relax in faith, trusting that God is able to run things without your help.
Twice in this passage it says, “Don’t be afraid,” and “Don’t be discouraged.” When you face a seemingly impossible situation, don’t be afraid and don’t be discouraged. Has God ever lost a battle? No. He doesn’t lose battles. 
There’s an important phrase in verse 17. God tells Jehoshaphat, “Take your positions and stand firm.” What does it mean to stand firm? It means to have a mental attitude of quiet confidence. It is never God’s will for you to run from a difficult situation. I’ve discovered that when I run from a difficult situation, inevitably God always brings it back around and gives me another chance. It’s inevitable. Why? 
Because God wants us to learn – and he wants to teach us through experience – that in every situation he is sufficient. He is competent and capable and he will meet our needs in that situation. Don’t be afraid; fear is the opposite of faith.