There's a really old prayer that goes something like "God, grant me the serenity to accept the things I cannot change, the courage to change the things I can, and the wisdom to know the difference."
I always thought it was a bit cliche, but I've realized more and more lately that it's actually very true. There are some things we cannot change ... that's what we need peace for. And there are some things we can change ... that's where the courage is needed.
But the real rubber hits the road when we can understand the difference. How many sleepless nights, fruitless days, and endless hours toiling have I spent trying to get the courage I needed when I needed peace? And how many situations have I given in to and said "well, that's my lot in life" when really, I just needed to man up and do what needed to be done?
May you and I have the wisdom we need to know when we need to seek peace and when we need to go to battle.