Joshua 1:9 says, “Have I not commanded you? Be strong and of good courage. Do not be terrified; do not be discouraged, for the LORD your God is with you wherever you go.”
 
The context of this verse is God, talking to Joshua, as he assumes leadership of Israel, prior to entering into the already inhabited Promised Land. I don't know about you, but it sounds like God is kind of annoyed by saying "Have I not commanded you?" But did he ever tell him this before? Well, actually, yes, he did in Deuteronomy 31:23.
 
The Lord gave this command to Joshua son of Nun: “Be strong and courageous, for you will bring the Israelites into the land I promised them on oath, and I myself will be with you” (Deuteronomy 31:23).
 
In fact, God says this to Joshua 6 times in Deuteronomy 31 and Joshua 1. Whenever something is repeated so many times, it must be important. Not only is this repeated many times in these two chapters it also is memorized and quoted generations later when David is speaking to his son Solomon. 
 
David also said to Solomon his son, “Be strong and courageous, and do the work. Do not be afraid or discouraged, for the Lord God, my God, is with you” (1 Chronicles 28:20a).

David repeats this to his son multiple times throughout 1 Chronicles 22-32.
 
What are you facing right now where you need God's message of strength, courage, and his presence?