By Faith Joseph…
That must have been a weird conversation. Joseph is at the end of his life (Hebrews 11:22). He gathers his family who are with him in Egypt and starts telling them these instructions that they need to pass on through the generations until the exodus. "The what?" they say.
Joseph dies. His sons die. One day his grandson calls his sons over and says, "I just remembered I'm supposed to give you a message from your great grandfather." He explains the strange message and tells them to pass it on.
Nothing indicates that God gave Joseph some sort of Revelation-like vision of the future. He gave these directions in faith. If Joseph could have faith that God would free thousands (millions?) of people from slavery just by deciding to do it, shouldn't I be able to believe that he could free me from my slavery to sin? But how do I really know that God will do this? As someone explained it to me: If God decides not to act in this way, that's up to him. But I'm not going to let my unbelief be the thing that holds it back. Like the father in Mark 9:24, "I believe, help my unbelief!".