Exodus 5:1-3

Young's Literal Translation

5 And afterwards have Moses and Aaron entered, and they say unto Pharaoh, `Thus said Jehovah, God of Israel, Send My people away, and they keep a feast to Me in the wilderness;'

² and Pharaoh saith, `Who [is] Jehovah, that I hearken to His voice, to send Israel away? I have not known Jehovah, and Israel also I do not send away.'

³ And they say, `The God of the Hebrews hath met with us, let us go, we pray thee, a journey of three days into the wilderness, and we sacrifice to Jehovah our God, lest He meet us with pestilence or with sword.'