Exodus 7:14-16

Young's Literal Translation

¹⁴ And Jehovah saith unto Moses, `The heart of Pharaoh hath been hard, he hath refused to send the people away;

¹⁵ go unto Pharaoh in the morning, lo, he is going out to the water, and thou hast stood to meet him by the edge of the River, and the rod which was turned to a serpent thou dost take in thy hand,

¹⁶ and thou hast said unto him: Jehovah, God of the Hebrews, hath sent me unto thee, saying, Send My people away, and they serve Me in the wilderness; and lo, thou hast not hearkened hitherto.