He alone is capable of removing from the heart of another doubt, deceit, fear or malice whose heart is already pure from these things or who, at least, can empty his heart of these things. There is a weakness of the heart and there is a strength of the heart. The heart's weakness is caused by things it contains which enfeeble it, such as doubt, deceit, fear and malice. The absence of these things produces that purity of heart which in itself is a power. This power could be increased by faith, hope and righteousness.