And thou shalt say unto him, The LORD God of the Hebrews hath sent me unto thee, saying, Let my people go, that they may serve me in the wilderness: and, behold, hitherto thou wouldest not hear.
You should tell him, "The Lord God of the Hebrews has sent me to you, saying let my people go so they can serve me in the wilderness, but so far you have not listened."