He delights not in the strength of the horse, nor does He take pleasure in the legs of a man. The Lord takes pleasure in those who reverently and worshipfully fear Him, in those who hope in His mercy and loving-kindness. [Ps. 145:20.] (Psalm 147:10, 11 AMP)
We can but we don't have to be battle ready. We can work out at the gym, we can jog, we can walk for a few miles. That's all very important on this earth. It all matters partially because you're at your best physically which in turn helps your spirit and soul. We're integrated people.
But God says there's something far more important. It's not our gym trips. It's how we worship Him...in spirit and truth. Do we worship Him reverently? He's merciful and full of lovingkindness.
When we have a battle of any kind, whether it's gossip about us, or fear inside, or family issues our battle is not against flesh and blood (Ephesians 6). That's why going to the gym and jogging are not quite as helpful as needed. God wants us to be on our knees figuratively, praying and worshiping. He's worth every moment of worship. And He'll be on our side to fight for us. There's a precious relationship between us and God when we worship, that surpasses any physical health or emotional weapons we could wield.