God prepared signs and wonders to prove himself and brought the Hebrews out of Egypt with a mighty hand. The first sign, and the first two plagues, the Pharaoh’s magicians were able to do as well; but they soon recognized a power greater than they could wield.
Note: I did my sermon prep using the ESV (English Standard Version) without doing a side-by-side comparison with the NKJV. The King James Version, and by extension the New King James, translates כֵּן (kēn) and lice whereas every modern translation seems to use gnats. At least one source states that lice, gnats or fleas are all possible translations. The Strong’s Hebrew number is 3654 if anyone would like to pursue this issue further.