Let me back up and explain something first, actually a couple of things:
#1 Not every battle we face is because of God or because of our faith. We bring some of our battles on ourselves. i.e. bad choices, bad company, rebellion, neglect are just a few of the things that can get us into trouble.
#2 Our sole purpose on this earth is not to grow rich, grow famous, get married, have kids, have a career, etc. Whatever prosperity we have is solely blessings from God, not what we deserve. Our purpose is to bring honor and glory to God, our creator.
Shock!!!... Do they tell you that in church. Probably not. Modern day churches preach as if God owes us something, when in fact it is just the opposite. We owe God EVERYTHING, literally.
Let's take a look back in history at some of God's warriors. (These aren't in any particular order or if they happen to be it is purely accidental. I am just listing them as they come to mind.)
First, Job, he was a man dearly loved by God. Did he do anything to cause the battles he endured? One thing, he loved God. He believed God. His battles drew him even closer to God. No matter what happened, he would not turn on God. In fact, he said in Job 19:25-26, "As for me, I know my Redeemer lives, and at the last He will take His stand on this earth. Even after my skin is destroyed, yet from my flesh I shall see God."
Can you imagine? Job lost his children, all his livestock, his home, everything dear to him. He had boils covering his body and yet HE DID NOT DENY GOD.
People tried to get him to admit he had done something to cause the curses that came on him. They thought surely he had to have done something. Job knew he hadn't but he knew God and he believed God. He was a warrior, chosen by God.
Shadrach, Meshach and Abednego being thrown into the fiery furnace, DID NOT DOUBT GOD. They told the king even if God did not save them, He was still God and they would not bow to another. Daniel 3:16-18, 16 Shadrach, Meshach and Abed-nego replied to the king, “O Nebuchadnezzar, we do not need to give you an answer concerning this matter. 17“If it be so, our God whom we serve is able to deliver us from the furnace of blazing fire; and He will deliver us out of your hand, O king. 18“But even if He does not, let it be known to you, O king, that we are not going to serve your gods or worship the golden image that you have set up.”
God's only son, Jesus, chosen by God Himself to be the one to die on the cross for us.
Every instance of every warrior, their faith did not waiver. When little David went up against the giant Goliath, he trusted God. When Daniel was thrown into the lion's den, he trusted God.
That is why God gives His toughest battles to His strongest warriors because through the battle their faith remains. There may be lapses of weakness but their faith does not waiver.