The secret of suffering

What enabled David to endure exile and kept him from taking matters into his own hands to curtail his suffering? He had a deep trust that God would reward him for doing the right thing even though it was causing him great pain. (1Sam 26:23-24) In Psalm 56:8-11 he reveals the secret of his perseverance. God was keeping track of his sorrows and was able to restore the wasted years. If God was on his side, men could not hurt him. If God is for us, who can be against us? He who did not spare his own Son, but delivered him up for us all, how will he not also with him freely give us all things? (Rom 8:31-32)