Whatever you believe is true, you are constantly teaching. Teaching is demonstration.
If you believe sickness and sin are real, you will demonstrate them by showing them in your body.
If you do not believe sickness and sin are real, the body will no longer be used to demonstrate a contradictory belief, and will be restored to health.
If you believe that God's truth is true, then you will not believe in sickness and death, and you will demonstrate this by proving that there are no causes outside of you, and therefore you, *symbolized by* your body, have not suffered any effects of separation.
Otherwise if the body remains sick, it is demonstrating and teaching to others that the Son of God can be sick, and that healing has not fully occurred. Sickness also demonstrates to others that they are guilty for causing the sickness, which is hardly an enlightened teaching.
This is why it is not enough just to convince yourself that you believe in God's truth, in some detached intellectual way. You must LIVE IT. You must demonstrate it and show it, in order to teach your brother that He is innocent, BECAUSE He cannot do anything to cause sickness in your body due to your mind's correctness.
You are supposed to be the "living proof" of miracles!