"'The elders of Israel will listen to you. Then you and the elders are to go to the king of Egypt and say to him, "The Lord, the God of the Hebrews, has met with us. Let us take a three-day journey into the desert to offer sacrifices to the Lord our God." But I know that the king of Egypt will not let you go unless a mighty hand compels him. So I will stretch out my hand and strike the Egyptians with all the wonders that I will perform among them. After that, he will let you go.'" NIV translation
God assures Moses that the elders will be on board and then goes on to give His complete plan for the deliverance of Israel. We might ask ourselves why God would have them tell Pharaoh that they were to go out on a three-day journey. The simple fact is that God was testing Pharaoh's heart even though He knew the outcome. We might also ask why God laid out the whole plan for Moses but many times it seems like He only gives us our next step. The simple answer is that Moses was not going to have the presence of God with him as he dealt with Pharaoh. God only gives us the next step we need to take because He will always be there with us through the Spirit to give us the next step when it is time.
"'And I will make the Egyptians favorably disposed toward this people, so that when you leave you will not go empty-handed. Every woman is to ask her neighbor and any woman living in her house for articles of silver and gold and for clothing, which you will put on your sons and daughters. And so you will plunder the Egyptians.'" NIV translation
The Hebrews had been slaves for many years but God assured Moses that they would receive the wages for their work.