C. F. Keil and Franz Delitzsch on Exodus 5:3

Exo 5:3

The messengers founded their request upon the fact that the God of the Hebrews had met them (נקרא, vid., Exo 3:18), and referred to the punishment which the neglect of the sacrificial festival demanded by God might bring upon the nation. פּן־יפגּענוּ: “lest He strike us (attack us) with pestilence or sword.” פּגע: to strike, hit against any one, either by accident or with a hostile intent; ordinarily construed with בּ, also with an accusative, 1Sa 10:5, and chosen here probably with reference to נקרא = נקרה. “Pestilence or sword:” these are mentioned as expressive of a violent death, and as the means employed by the deities, according to the ordinary belief of the nations, to punish the neglect of their worship. The expression “God of the Hebrews,” for “God of Israel” (Exo 5:1), is not chosen as being “more intelligible to the king, because the Israelites were called Hebrews by foreigners, more especially by the Egyptians (Exo 1:16; Exo 2:6),” as Knobel supposes, but to convince Pharaoh of the necessity for their going into the desert to keep the festival demanded by their God. In Egypt they might sacrifice to the gods of Egypt, but not to the God of the Hebrews.