Exodus 8:
Ellicott explained:26 But Moses said, "That would not be right. The sacrifices we offer the LORD our God would be detestable to the Egyptians. And if we offer sacrifices that are detestable in their eyes, will they not stone us?
The sacrificial animals of the Hebrews—sheep, goats, and cattle—were all of them sacred animals, either to the Egyptians generally, or to the inhabitants of certain districts. A Theban could not endure the sacrifice of a sheep, nor a Men-desian that of a goat (Herod. ii. 42). White cows and heifers—perhaps cows and heifers generally—were sacred to Isis-Athor. Any bull-calf might be an Apis; and it could not be known whether he was Apis or not till the priests had examined him (Herod. iii. 28). The extent to which the Egyptians carried their rage when a sacred animal was killed in their presence is illustrated by many facts in history. On one occasion a Roman ambassador, who had accidentally killed a cat, was torn to pieces by the populace (Diod. Sic. i. 83). On another, war broke out between the Oxyrinchites and the Cynopolites, because the latter had eaten one of the fish considered sacred by the former (Plutarch, De Isid. et Osir. § 44). The fear of Moses was thus not at all groundless.