Joshua 1:9

“Have I not commanded you? Be strong and courageous. Do not be frightened, and do not be dismayed, for the Lord your God is with you wherever you go.”

Where it comes from

Moses has died, and Joshua has just been handed the job of leading an entire nation across a river into a land full of walled cities. God says "be strong and courageous" to him three times in nine verses. He clearly needed to hear it.

What it means

Courage in the Bible is never about not being afraid. Joshua was told not to be frightened precisely because he was. The reason given is not that the task is easy or that he is capable. It is that God goes with him, everywhere, with no exceptions. That is the verse people reach for on the first day of a new job, a deployment, a diagnosis, or a move across the country.