So many talk about the purification of heart, and so few really know what it is. Some say to be pure means to be free from all evil thought of bitterness against another. No one with sense and understanding would like to keep a drop of poison in his body, and how ignorant it is on the part of man when he keeps and cherishes a bitter thought against another in his heart. If a drop of poison can cause the death of the body, it is equal to a thousand deaths when the heart retains the smallest thought of bitterness.