Joshua was either born in Egypt or the Wilderness. He was growing up seeing and hearing about all that God had been faithful to do for the Israelites when they obeyed God. He was probably taught well about the things of God and may have been really close to Moses since his father worked for Moses personally. It's hard to think about Joshua (of all people) having to be told to be strong and courageous.
The thing is though, no matter how many times you see God move "mountains" for other people in their lives it can be hard to have faith that He can move them for you. I have had the privilege of seeing God move both small and enormous "mountains" in my own life. My faith has grown tremendously and my relationship with Him is in constant growth. But the next time I face a mountain I will comfort myself with these words God spoke over Joshua.
Joshua has heard stories of God's faithfulness and witnessed first hand God deliver the Israelites from their "mountains". Joshua still needed God to affirm him and remind him that God would never forsake him and was indeed calling him up to lead his people into the Promised Land.
In verse 5-9 God says,
"No man shall be able to stand before you all the days of your life; as I was with Moses, so I will be with you. I will not leave you nor forsake you.
Be strong and of good courage, for to this people you shall divide as an inheritance the land which I swore to their fathers to give them.
Only be strong and very courageous, that you may observe to do according to all the law which Moses My servant commanded you; do not turn from it to the right hand or to the left; that you may prosper wherever you go.
This Book of the Law shall not depart from your mouth, but you shall meditate in it day and night, that you may observe to do according to all that is written in it. For then you will make your way prosperous, and then you will have good success.
Have I not commanded you? Be strong and of good courage; do not be afraid, nor be dismayed, for the Lord your God is with you wherever you go."
So far Joshua's been told to be strong and of good courage three times. I think He's going to need to be strong and courageous don't you?
We can learn from Joshua that if we decide to be strong and courageous to walk in what God's called us to do God will be faithful to equip us with what we need to accomplish what He has planned for us.
God has gone before us and has already defeated the enemy. God will not forsake us EVER. The way we guard ourselves is to study God's Word. Meditate on it. Obey what it says. Speak it. Pray it. If we do this we will prosper and have good success. Do not be afraid. BE STRONG AND COURAGEOUS!!!