I read of a boy living by the sea who loved nothing more than building castles in the sand. Every day after school he would build them of different shapes and sizes, and every day a group of bullies from school would destroy them. Then one day, on a tip from his grandpa, the boy put chunks of concrete and cinder block in the base of the castles. The next time the bullies came to destroy, they stubbed their toes and feet. Even castles made of sand become impregnable when they are built upon a rock.
Believers are vulnerable too to the attacks of the enemy, to the weaknesses of the flesh.
But when their lives are built on the Rock, they are strong to withstand anything. This Rock is Jesus not facts about Jesus, not blessings from Jesus, not even just the teachings of Jesus, but Jesus Christ Himself. It is not getting people to doctrine, but getting people to Jesus, that is the priority of our mission, and once they get to Him they will be shocked at what they find. Jesus is both more gracious and more terrifying than people think. Jesus is not asking about faith in the doctrine or faith in the denomination.