A person has died. During his lifetime for [one] reason or another he did not concern himself with spiritual science. The one who remains behind on earth can know by means of spiritual science that the deceased has a burning thirst for spiritual science. Now if the one who remains behind concerns himself with thoughts of a spiritual nature as if the dead were there with him, he performs a great service to him. We can actually read to the dead. That enables the gulf that exists between the living and the dead to be bridged. The two worlds, the physical and the spiritual, are severed by materialism. Consider how their union will take hold of life itself! When spiritual science does not remain mere theory but becomes a life impulse as it should, there will not be separation but immediate communication. By reading to the dead we can enter in immediate connection with them and help them. The one who has avoided spiritual science will continue to feel the anguish of longing for it unless we help him. We can assist him from the earth if such a longing is at all present. By this means the living can help the dead.
Source: Rudolf Steiner – GA 140 – Life Between Death and Rebirth: VII: The Working of Karma in Life After Death – Bern, December 15, 1912