The religion of God has two aspects in this world. The spiritual (the real) and the formal (the outward). The formal side changes, as man changes from age to age. The spiritual side which is the Truth, never changes. The Prophets and Manifestations of God bring always the same teaching; at first men cling to the Truth but after a time they disfigure it. The Truth is distorted by man-made outward forms and material laws. The veil of substance and worldliness is drawn across the reality of Truth.
- 'Abdu'l-Baha (Words of ‘Abdu’l-Baha, ‘Abdu'l-Baha in London’, Notes of Conversations)