Exodus 5:1-2

1And afterward Moses and Aaron came and said to Pharaoh, “1This is what the Lord, the God of Israel says: ‘2Let My people go so that they may celebrate a feast to Me in the wilderness.’”

2But Pharaoh said, “3Who is the Lord that I should obey His voice to let Israel go? I do not know the Lord, and besides, 4I will not let Israel go.”