Charles H. Spurgeon on Psalms 105:31

Lice in all their coasts. The priests, being polluted by this horrible infection, could not stand to minister before their deities. The people could not, in their uncleanness, be admitted within the precincts of their temples. If they would offer sacrifice, there were no victims fit for the purpose. Even the gods, the oxen, and goats, and cats, were defiled with the vermin. The Egyptians not only writhed under the loathsome scourge, but felt themselves humbled and disgraced by it. Josephus notices this: —"Pharaoh, "he says, "was so confounded at this new plague, that, what with the danger, the scandal, and the nastiness of it, he was half sorry for what he had done" (b. it. c. 14). The plague assumed the form of a disease, being "in the people." Ex 8:17. As Josephus says again, "The bodies of the people bred them, and they were all covered over with them, gnawing and tearing intolerably, and no remedy, for baths and ointments did no good." But, however distressing to their bodies, the foul and disgraceful character of the plague, and the offence brought upon their religion by the defilement of their deities and the interruption of all their religious ceremonies, was its most offensive feature. Thomas S. Millington.