John Gill Commentary Ezekiel 31:2

"Son of man, say unto Pharaoh king of Egypt, and to his multitude: Whom art thou like in thy greatness?" — Ezekiel 31:2 (ASV)

Son of man, speak to Pharaoh king of Egypt
To Pharaohhophra, the then reigning king; not to him personally by word of mouth, for the prophet was now in Chaldea; but by delivering out a prophecy concerning him, and which he might have an opportunity of sending to him.

and to his multitude ;
the multitude of his subjects, of which he boasted, and in whom he trusted.

whom are you like in your greatness ?
Look over all the records of time, and into all the empires, kingdoms, and states that have been; draw a comparison between yourself and the greatest potentate that ever was; fancy yourself to be equal to him; this will not secure you from ruin and destruction; for as they have been humbled, and are fallen, so will you be: pitch for instance on the Assyrian monarch, whose empire has been the most ancient, extensive, and flourishing, and yet now crushed; and as you are like him in greatness, at least you think so, so you are in your end; to assure of which is the drift of the following account of the king of Assyria.