He may have been surprised or scared. It was a big job. There were over two million people that were going to be doing what he said.
It is hard to make a decision when it is for yourself, but he had to do it for many people. Before he did anything else, Joshua talked to the Lord. God told him to, "Be strong and of a good courage; be not afraid... for the Lord thy
God is with thee wherever you go."
Then as Joshua went among the people, they encouraged Joshua. They said they would follow Joshua as they had followed Moses.
God gave Joshua the assurance that it was the right thing to do. He will lead you, if you will listen and obey.
You do not have to be afraid, if you are following Jesus. He promises to be with you always. You can have His peace and joy. It is not how big the job is. It is how you trust your God.
Joshua did great things for God. First he did the little things, and then God gave him bigger jobs. You must do the same thing. You must be faithful in the little things, so God can give you bigger jobs to do.
He wants to do great things through you; trust Him today.