Exodus 6:28-30

Young's Literal Translation

²⁸ And it cometh to pass in the day of Jehovah's speaking unto Moses in the land of Egypt,

²⁹ that Jehovah speaketh unto Moses, saying, `I [am] Jehovah, speak unto Pharaoh king of Egypt all that I am speaking unto thee.'

³⁰ And Moses saith before Jehovah, `Lo, I [am] of uncircumcised lips, and how doth Pharaoh hearken unto me?'