The law of God includes a law that annuls every false claim, and we know it and must use it. Mental activity must be tranquil — not lazy; it must express force, be exact and it must know the reality of man’s oneness with God, and the utter unreality of evil in all its forms of beliefs. Know there is no mental or material poison; no substance or mind to contain or manifest poison, irritation or inflammation; no organism or substance that can give forth impurities; no impeded circulation or imperfect action. We cannot be made apathetic or forgetful, for God is our guide and instructor. Mary Baker Eddy (Carpenter, Gilbert, Collectanea of Items By and About Mary Baker Eddy, p.131)