Deuteronomy 31:7 And Moses called unto Joshua, and said unto him in the sight of all Israel, Be strong and of a good courage: for thou must go with this people unto the land which the LORD hath sworn unto their fathers to give them; and thou shalt cause them to inherit it.
God told Moses and He also tells Joshua that He is going to take the promised land. It was after all the promised land, meaning that God had promised to give it to them.
God had sworn to give the people the land. God had chosen to use Joshua to do that. He now hears that spoken very plainly. God will use you to cause them to inherit the land.
Who couldn’t go forward with good encouragement after hearing such words. God is going to do this work and He is going to use you.
I think it is easy to see how Joshua should have believed and even question his lack of faith. But we have the same promises. God is going to use us. We are going to see God do great things. We are His people sent to do His work.
We are also guaranteed success. We should step out in faith believing God.