Exodus 3:18

And they shall hearken to thy voice; and thou shalt come, thou and the elders of Israel, unto the king of Egypt, and ye shall say unto him, The Lord God of the Hebrews hath met with us, for the present revelation of God to Moses concerned, and had significance for, all the people; and now let us go, we beseech thee, three days' journey into the wilderness, that we may sacrifice to the Lord, our God. This request was not a deception, but agreed with the plan of God, for because the Lord knew the hard heart of Pharaoh, Moses and the elders were, at the beginning, not to ask more than a leave of absence, for Pharaoh's denial of this petition would then reveal the hardness of his heart. God intended to make Pharaoh an example for all time.