Now know I that the Lord is greater than all gods. It would seem that Jethro, like the generality of the heathen, believed in a plurality of gods, and had hitherto regarded the God of the Israelites as merely one among many equals.
Now, he renounces this creed, and emphatically declares his belief that Jehovah is above all other gods, greater, higher, more powerful. Compare the confessions of Nebuchadnezzar (Daniel 2:47; Daniel 3:26, Daniel 3:27) and Darius the Mede (Daniel 6:26).
For in the thing wherein they dealt wickedly he was above them. There is no "he was above them" in the original, nor is the clause a distinct sentence from the preceding one. It is merely a prolongation of that clause, without any new verb; and should be translated, "Even in the very matter that they (the Egyptians) dealt proudly against them "(the Israelites).
The superiority of Jehovah to other gods was shown forth even in the very matter of the proud dealing of the Egyptians, which was brought to shame and triumphed over by the might of Jehovah. The allusion is especially to the passage of the Red Sea.