Lewis Spence said this quote
“ Here it is necessary briefly to consider the question of the cult of ancestors before venturing farther. The spirits of the departed are believed to be possessed of supernatural powers which they did not enjoy in the flesh. They may also be dissatisfied or malignant in consequence of being suddenly deprived of life, and if they are neglected by the living, are apt to be revengeful. Therefore they must be cajoled and propitiated. Fear of beings belonging to a mysterious state or sphere of which he knew nothing continually haunted and terrified primitive man and induced in him what is known as the dread of the sacred. It was every man's personal duty to attend to the demands or requirements of his deceased ancestors. At first he would succour his own immediate forebears with food and gifts; but it must have been borne in upon him that when his parents joined the great majority, the care of the spirits of their parents likewise devolved upon him... and, by degrees, he might even come to regard himself as responsible for the well-being of a line of spirit ancestors of quite formidable genealogy. These, through his neglect, might starve in their tombs; or, alternatively, they might crave his company. Because of vengeance or loneliness they might send disease upon him, for the savage almost invariably believes illness to be brought about by the action of jealous or neglected ancestors. The loneliness of the spirit-world is the dead man's greatest excuse for desiring the company of his descendants. ”