Her. 2.37 (further on the Egyptian character)
They are religious beyond measure, more than any other people. Among their customs: They drink from cups of bronze, which they clean out daily; this is done not by some but by all.  They are especially careful always to wear newly-washed linen. They practise circumcision for cleanliness; for they would rather be clean than attractive.
Their priests shave the whole body every other day, so that no lice or anything else foul may infest them as they attend upon the gods.  The priests wear a single linen garment and sandals of papyrus:1 they may have no other kind of clothing or footwear. Twice a day and twice every night they wash in cold water. Their religious observances are, one may say, innumerable.  But also they receive many benefits: they do not consume or spend anything of their own; sacred food is cooked for them, beef and goose are brought in great abundance to each man every day, and wine of grapes is given to them, too. They may not eat fish.  They sow no beans in their country; if any grow, they will not eat them either raw or cooked; the priests cannot endure even to see them, considering beans an unclean kind of legume. Many (not only one) are dedicated to the service of each god. One of these is the high priest; and when a high priest dies, his son succeeds to his office.
(38) They believe that bulls belong to Epaphus (=Apis) and for this reason scrutinize them as follows; if they see even one black hair on them, the bull is considered impure.  One of the priests, appointed to the task, examines the beast, making it stand and lie, and drawing out its tongue, to determine whether it is clean of the stated signs which I shall indicate hereafter.2 He looks also to the hairs of the tail, to see if they grow naturally.  If it is clean in all these respects, the priest marks it by wrapping papyrus around the horns, then smears it with sealing-earth and stamps it with his ring; and after this they lead the bull away. But the penalty is death for sacrificing a bull that the priest has not marked. ...
(41). All Egyptians sacrifice unblemished bulls and bull-calves; they may not sacrifice cows: these are sacred to Isis.  For the images of Isis are in woman's form, horned like a cow, exactly as the Greeks picture Io, and cows are held by far the most sacred of all beasts of the herd by all Egyptians alike.  For this reason, no Egyptian man or woman will kiss a Greek man, or use a knife, or a spit, or a cauldron belonging to a Greek, or taste the flesh of an unblemished bull that has been cut up with a Greek knife.  Cattle that die are dealt with in the following way. Cows are cast into the river, bulls are buried by each city in its suburbs, with one or both horns uncovered for a sign; then, when the carcass is decomposed, and the time appointed is at hand, a boat comes to each city from the island called Prosopitis,  an island in the Delta, ...
(42). All that have a temple of Zeus of Thebes or are of the Theban district sacrifice goats, but will not touch sheep.  For only Isis and Osiris are worshipped by all Egyptians in common; [most of the gods belong to a particular region or cult] Osiris they say is Dionysus; he and Isis are worshipped by all alike. Those who have a temple of Mendes (=Pan?) or are of the Mendesian district sacrifice sheep, but will not touch goats.
 The Thebans, and those like them who will not touch sheep, give the following reason for their ordinance: they say that Heracles wanted very much to see Zeus and that Zeus did not want to be seen by him, but that finally, when Heracles prayed, Zeus contrived  to show himself displaying the head and wearing the fleece of a ram which he had flayed and beheaded. It is from this that the Egyptian images of Zeus have a ram's head; and in this, the Egyptians are imitated by the Ammonians, who are colonists from Egypt and Ethiopia [at Oasis/Siwa in Libya] and speak a language compounded of the tongues of both countries.  It was from this, I think, that the Ammonians got their name, too; for the Egyptians call Zeus “Amon”. The Thebans, then, consider rams sacred for this reason, and do not sacrifice them.  But one day a year, at the festival of Zeus, they cut in pieces and flay a single ram and put the fleece on the image of Zeus, as in the story; then they bring an image of Heracles near it. Having done this, all that are at the temple mourn for the ram, and then bury it in a sacred coffin.
(43). Concerning Heracles, I heard it said that he was one of the twelve gods. But nowhere in Egypt could I hear anything about the other Heracles, whom the Greeks know.  I have indeed a lot of other evidence that the name of Heracles did not come from Hellas to Egypt, but from Egypt to Hellas (and in Hellas to those Greeks who gave the name Heracles to the son of Amphitryon), besides this: that Amphitryon and Alcmene, the parents of this Heracles, were both Egyptian by descent; and that the Egyptians deny knowing the names Poseidon and the (sons of Zeus) Dioscuri, nor are these gods reckoned among the gods of Egypt.  Yet if they got the name of any deity from the Greeks, of these not least but in particular would they preserve a recollection, if indeed they were already making sea voyages and some Greeks, too, were seafaring men, as I expect and judge; so that the names of these gods would have been even better known to the Egyptians than the name of Heracles.  But Heracles is a very ancient god in Egypt; as the Egyptians themselves say, the change of the eight gods to the twelve, one of whom they acknowledge Heracles to be, was made seventeen thousand years before the reign of Amasis.
(45). The Greeks say may silly things, such as the tale they tell about Heracles: that when he came to Egypt, the Egyptians crowned him and led him out in a procession to sacrifice him to Zeus; and for a while (they say) he followed quietly, but when they started in on him at the altar, he resisted and killed them all.  Now it seems to me that by this story the Greeks show themselves altogether ignorant of the character and customs of the Egyptians; for how should they sacrifice men when they are forbidden to sacrifice even beasts, except swine and bulls and bull-calves, if they are unblemished, and geese?  And furthermore, as Heracles was alone, and, still, only a man, as they say, how is it natural that he should kill many myriads? Though I say so much about this, may I keep the goodwill of gods and heroes!
(45) To Dionysus, on the evening of his festival, everyone offers a piglet which he kills before his door and then gives to the swineherd who has sold it, for him to take away.  The rest of the festival of Dionysus is observed by the Egyptians much as it is by the Greeks, except for the dances; but in place of the phallus, they have invented the use of puppets two feet high moved by strings, the male member nodding and nearly as big as the rest of the body, which are carried about the villages by women; a flute-player goes ahead, the women follow behind singing of Dionysus.  Why the male member is so large and is the only part of the body that moves, there is a sacred legend that explains....
(50) In fact, the names of nearly all the gods came to Hellas from Egypt. For I am convinced by inquiry that they have come from foreign parts, and I believe that they came chiefly from Egypt.  Except the names of Poseidon and the Dioscuri [sons of Zeus, guardians of seafarers] as I have already said, and Hera, and Hestia, and Themis, and the Graces, and the Nereids, the names of all the gods have always existed in Egypt. I only say what the Egyptians themselves say. The gods whose names they say they do not know were, as I think, named by the Pelasgians, except Poseidon, the knowledge of whom they learned from the Libyans.  Alone of all nations the Libyans have had among them the name of Poseidon from the beginning, and they have always honored this god. The Egyptians, however, are not accustomed to pay any honors to heroes.
(51). These customs, then, and others besides, which I shall indicate, were taken by the Greeks from the Egyptians. It was not so with the ithyphallic images of Hermes; the production of these came from the Pelasgians, from whom the Athenians were the first Greeks to take it, and then handed it on to others....
(52) Formerly, in all their sacrifices, the Pelasgians called upon gods without giving name or appellation to any (I know this, because I was told at the shrine of Zeus at Dodona); for as yet they had not heard of [ calling gods by name]. They called them’ gods’ [=theoi, as though from theinai, ‘to set’] from the fact that they ‘set’ everything in order... Then, after a long while, first they learned the names of the rest of the gods, which came to them from Egypt, and, much later, the name of Dionysus; and presently they asked the oracle at Dodona about the names; for this place of divination, held to be the most ancient in Hellas, was at that time the only one.  When the Pelasgians, then, asked at Dodona whether they should adopt the names that had come from foreign parts, the oracle told them to do so. From that time onwards they used the names of the gods in their sacrifices; and the Greeks received these later from the Pelasgians.
(53) But whence each of the gods came to be, or whether all had always been, and how they appeared in form the Greeks knew nothing until yesterday or the day before, so to speak;  for I suppose Hesiod and Homer flourished not more than four hundred years earlier than I; and these are the ones who taught the Greeks the descent of the gods, and gave the gods their names, and determined their spheres and functions, and described their appearance.