Exodus 6:30 YLT

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?'