Be strong and courageous

Joshua 1:9 – “I command you – be strong and courageous! Do not be afraid or discouraged. For the Lord your God is with you wherever you go.”

What does it mean to be ‘strong and courageous’ today? I realize this passage was referring to a specific point in the history of Israel, but there are references in the New Testament to ‘boldness’, ‘confidence’, etc. What does this look like? Do I see this in people very often? Have so many of us been ‘burned’ by past experiences and are constantly questioning whether we are ‘right’ or know the ‘truth’ or are actually following God’s will that we do not possess confidence and boldness in our walk of faith?

How does a person become strong in the Lord?