Other confirmatory evidence of the presence of the concept of a high god will be found in the account of various ceremonies.
There is no doubt about the definition of the concept of the imu, and it can be translated as the spirit of the deceased person.
The Kitui elders stated that the sacrificial fire for cooking the meat at the ithembo must always be made by friction, so as to avoid any such impurity or uncleanness being brought from a house as might occur were burning embers from a household kitchen taken to the tree.
No one who is under a thabu or tabu can take part in a ceremony at an ithembo, nor must the muma or kithito oath be taken on such an occasion. Inquiries [[64]]were made as to whether, in olden times, any of the spoils of war were sacrificed at an ithembo, but this was said not to have been the case.
When, as sometimes happens, a shooting star appears to fall in an ithembo, it is supposed to be a sign that Engai has descended to the ithembo and demands food. Various kinds of food are then taken there as offerings. It is, however, not usual to sacrifice an animal. The shooting star falling on an ithembo may be compared with the story of Jehovah appearing to Moses in a burning bush, which seemed to burn and yet not be consumed. It is here to be noted that it is Engai who demands food, not the aiimu.
Sacrifice apparently is only performed when the people desire to invoke help.
One elder only from each clan, mbai, can participate in a ceremony at the ithembo on any particular occasion, and, further, no elder whose father is alive can go to the tree.
If in war an enemy took sanctuary at an ithembo he was allowed to stay there unmolested, and was safe; at night he escaped. If, again, he caught hold of an elder of ithembo, he was equally safe; the elder would take him to his village and send one of his sons to convey him safely out of the country. It is considered that this fact emphasises the priestly position of the elders of ithembo, who must, at all cost, avoid the stain of death.
If a snake is seen at a sacred place it is customary to pour milk, butter, and gruel over it; it is supposed to be njoka ya aiimu (snake of the aiimu).
Arms must not be taken to an ithembo, small knives to skin the sacrificial animals only being allowed.