The physical body of a man was called KHAT, a word which indicates something in which decay is inherent; it was this which was buried in the tomb after mummification, and its preservation from destruction of every kind was the object of all amulets, magical ceremonies, prayers, and formulae, from the earliest to the latest times.
The god Osiris even possessed such a body, and it's various members were preserved as relics in several shrines in Egypt.
Attached to the body in some remarkable way was the KA, or "double," of a man; it may be defined as an abstract individuality or personality which was endowed with all his characteristic attributes, and it possessed an absolutely independent existence. It was free to move from place to place upon earth at will, and it could enter heaven and hold converse with the gods.
The offerings made in, the tombs at all periods were intended for the nourishment of the KA, and it was supposed to be able to eat and drink and to enjoy the odor of incense.
In the earliest times, a certain portion of the tomb was set apart for the use of the KA, and the religious organization of the period ordered that a class of priests should perform ceremonies and recite prayers at stated seasons for the benefit of the KA in the KA chapel; these men were known as "KA priests."
The soul was called BA, and the ideas which the Egyptians held
concerning it are somewhat difficult to reconcile; the meaning of the
word seems to be something like "sublime," "noble," "mighty."
The BA dwelt in the KA, and seems to have had the power of becoming corporeal or incorporeal at will; it had both substance and form and is frequently depicted on the papyri and monuments as a human-headed hawk;
in nature and substance, it is stated to be ethereal. It had the power to
leave the tomb, and to pass up into heaven where it was believed to
enjoy an eternal existence in a state of glory; it could, however, and
did, revisit the body in the tomb, and from certain texts, it seems that
it could re-animate it and hold converse with it.
Like the heart AB it was, in some respects, the seat of life in man. The souls of the blessed dead dwelt in heaven with the gods, and they partook of all the celestial enjoyments forever.
The spiritual intelligence, or spirit, of a man was called KHU, and it
seems to have taken form as a shining, luminous, intangible shape of the
body; the KHUs formed a class of celestial beings who lived with the
gods, but their functions are not clear. The KHU, like the KA, could be
imprisoned in the tomb,
Besides the KHU another very important
part of a man's entity went into heaven, namely, his SEKHEM. The word
literally means "to have the mastery over something," and, as used in
the early texts, that which enables one to have the mastery over
something; _i.e._, "power." The SEKHEM of a man was, apparently, his
vital force or strength personified, and the Egyptians believed that it
could and did, under certain conditions, follow him that possessed it
upon earth into heaven.
Another part of a man was the KHAIBIT or "shadow," which is frequently mentioned in connexion with the soul and, in late times, was always thought to be near it.
Finally, we may mention the REN, or "name" of a man, as one of his most important constituent parts. The Egyptians, in common with all Eastern nations, attached the greatest importance to the preservation of the name, and any person, who effected the blotting out of a man's name was thought to have destroyed him also.
Like the KA it was a portion, of a man's most special identity, and it is easy to see why so much importance grew to be attached to it; a nameless being could not be introduced to the gods, and as no created thing exists without a name the man who had no name was in a worse position before the divine powers than the feeblest inanimate object.
We have seen that the entity of a man consisted of body, double, soul, heart, spiritual intelligence or spirit, power, shadow, and name.