פירוש על שמות 8:17

משליח בך means I WILL INCITE AGAINST THEE. Another example is. (Deuteronomy 32:24) “I will incite (אשלח) the tooth of beasts against them”, where it signifies letting loose an animal against a person; old French inciter. English to incite.

והערוב, I believe that the Torah describes different kinds of wolves that are known by the word ,ערוב seeing that it is their habit to hunt at night as we know from Jeremiah 5,6. as well as from Tzefaniah 3,3. The fact that the wolf sets out when it gets dark, in the evening, and does not return until morning, is why this animal is referred to as ערוב, describing its habits.

וגם האדמה אשר הם עליה, a reference to the soil on which the houses stood which would become full of snakes and other creepers of the kind that inhabit the lower levels of the earth beneath its surface. The plague would result in the Egyptians feeling insecure in their homes even when they had shut every exit tightly.