verses 16-17
The Gnats, or the third plague. - The כּנּם, or כּנּים (also כּנּם, probably an old singular form, Ewald, §163f), were not “lice,” but σκνῖφες, sciniphes, a species of gnats, so small as to be hardly visible to the eye, but with a sting which, according to Philo and Origen, causes a most painful irritation of the skin. They even creep into the eyes and nose, and after the harvest they rise in great swarms from the inundated rice-fields. This plague was caused by the fact that Aaron smote the dust of the ground with his staff, and all the dust throughout the land of Egypt turned into gnats, which were upon man and beast (Exo 8:17). “Just as the fertilizing water of Egypt had twice become a plague, so through the power of Jehovah the soil so richly blessed became a plague to the king and his people.”
verses 18-19
“The magicians did so with their enchantments (i.e., smote the dust with rods), to bring forth gnats, but could not.” The cause of this inability is hardly to be sought for, as Knobel supposes, in the fact that “the thing to be done in this instance, was to call creatures into existence, and not merely to call forth and change creatures and things in existence already, as in the case of the staff, the water, and the frogs.” For after this, they could neither call out the dog-flies, nor protect their own bodies from the boils; to say nothing of the fact, that as gnats proceed from the eggs laid in the dust or earth by the previous generation, their production is not to be regarded as a direct act of creation any more than that of the frogs. The miracle in both plagues was just the same, and consisted not in a direct creation, but simply in a sudden creative generation and supernatural multiplication, not of the gnats only, but also of the frogs, in accordance with a previous prediction. The reason why the arts of the Egyptians magicians were put to shame in this case, we have to seek in the omnipotence of God, restraining the demoniacal powers which the magicians had made subservient to their purposes before, in order that their inability to bring out these, the smallest of all creatures, which seemed to arise as it were from the dust itself, might display in the sight of every one the impotence of their secret arts by the side of the almighty creative power of the true God. This omnipotence the magicians were compelled to admit: they were compelled to acknowledge, “This is the finger of God.” “But they did not make this acknowledgment for the purpose of giving glory to
