John Gill Commentary Exodus 7:2

"Thou shalt speak all that I command thee; and Aaron thy brother shall speak unto Pharaoh, that he let the children of Israel go out of his land." — Exodus 7:2 (ASV)

You shall speak all that I command you. That is, to Aaron his prophet, whatever the Lord made known to him in a private manner as his will to be done.

And Aaron your brother shall speak to Pharaoh; whatever should be told him by Moses, as from the Lord.

That he send the children of Israel out of his land; this was the principal thing to be insisted upon.

And all that was said or done to him was to bring about this end, the dismission of the children of Israel out of Egypt.