Now the Lord said to Joshua, “This day I will begin to exalt you in the sight of all Israel, that they may know that just as I have been with Moses, I will be with you.” (v.7)
God told Joshua that He was about to exalt him, not so the Israelites would know of Joshua's greatness, but rather that they would know the Lord was with him. Joshua was now leading people who were not alive to see the parting of the Red Sea. Most of them didn't know any life other than the wandering wilderness. They had not witnessed first-hand some of God's miraculous provision. So God was about to give them a sign that would remove any and all doubt of Joshua’s leadership.
As all of Israel stood in formation over half a mile away from the “ark of the covenant," the priests carried it to the overflowing Jordan River. Their faith was about to be tested in a task that required them to put their trust in God and the words He spoke through His servant Joshua, “When the soles of the feet of the priests who carry the ark of the Lord, the Lord of all the earth, rest in the waters of the Jordan, the waters of the Jordan will be cut off, and the waters which are flowing down from above will stand in one heap.” (v.13) Wow, instant credibility or not.
It's a lot easier to be a leader, when the people you're leading trust you. Most leaders have to earn that trust over time, but God gave Joshua a huge endorsement here. For as the priests feet entered the Jordan, “the water rose up in one heap and the people crossed over opposite Jericho on dry ground.” (v.16) This miracle obviously connects with the miracle the nation experienced some 40 years earlier: the passing through the Red Sea. God brought the previous generation out of Egypt’s bondage with that miracle, and He now brings the current generation into the Promised Land with a similar miracle.
The application here for us is, fear fads when we trust God, and He will never ask you to go where He does not lead. Sometimes He'll use you to show His glory, other times He'll just remind you of His presence. No matter the situation, He is faithful to help you fulfill the tasks He gives you to complete.
The Truth: "I will instruct you and teach you in the way you should go; I will guide you with My eye" (Psalm 32:8)