Exodus 3:18

Then a fugitive came and told Abram the Hebrew. Now he was dwelling by the oaks of Mamre the Amorite, brother of Eshcol and brother of Aner, and these were in a covenant with Abram.

Then Moses answered and said, “What if they will not believe me and will not listen to my voice? For they may say, ‘Yahweh has not appeared to you.’”

So the people believed; and they heard that Yahweh cared about the sons of Israel and that He had seen their affliction. So they bowed low and worshiped.

And afterward Moses and Aaron came and said to Pharaoh, “Thus says Yahweh, the God of Israel, ‘Let My people go that they may celebrate a feast to Me in the wilderness.’”

Then they said, “The God of the Hebrews has met with us. Please, let us go a three days’ journey into the wilderness that we may sacrifice to Yahweh our God, lest He confront us with pestilence or with the sword.”

“And you shall say to him, ‘Yahweh, the God of the Hebrews, sent me to you, saying, “Let My people go, that they may serve Me in the wilderness. But behold, you have not listened until now.”

Then Yahweh said to Moses, “Come to Pharaoh and say to him, ‘Thus says Yahweh, “Let My people go, that they may serve Me.

And Yahweh said to Moses, “Rise early in the morning and stand before Pharaoh as he comes out to the water, and you shall say to him, ‘Thus says Yahweh, “Let My people go, that they may serve Me.

“We must go a three days’ journey into the wilderness and sacrifice to Yahweh our God as He says to us.”

Then Yahweh said to Moses, “Pass before the people and take with you some of the elders of Israel; and take in your hand your staff with which you struck the Nile, and go.