Moses
Exodus 9:10ESV·traditional attribution

So they took soot from the kiln and stood before Pharaoh. And Moses threw it in the air, and it became boils breaking out in sores on man and beast.

Matthew Henry Presbyterian @wholebiblehenry

Observe here, concerning the plague of boils and blains, I. When they were not wrought upon by the death of their cattle, God sent a plague that seized their own bodies, and touched them to the quick. If less judgments do not do their work, God will send greater.

Commenting on Exodus 9:8-12

John Gill Reformed Baptist @doctorgill

And they took ashes of the furnace,.... Which was near at hand, perhaps in Pharaoh's kitchen: and stood before Pharaoh; not in his palace, or in any covered room, but in some place open to the heaven, a courtyard or garden adjoining to the palace: and Moses sprinkled it up towards heaven; cast it up in the air; this being again ascribed to Moses, seems...

Jamieson-Fausset-Brown Reformed @jfbcommentary

PLAGUE OF BOILS. (Exo 9:8-17) Take to you handfuls of ashes, &c.--The next plague assailed the persons of the Egyptians, and it appeared in the form of ulcerous eruptions upon the skin and flesh (Lev 13:20; Kg2 20:7; Job 2:7). That this epidemic did not arise from natural causes was evident from its taking effect from the particular action of Moses done in the sight of Pharaoh.

Commenting on Exodus 9:8-17