Romans 15:4 says for whatever things were written before were written for our learning, that we through the [a]patience and comfort of the Scriptures might have hope.  We can learn from the mistakes that Israel made with their discouragement and lack of trust in God.  Numbers 33 tells us Israel left Egypt in boldness but along the way they started looking at things with their eyes and not by faith.  It was their lack of trust that  caused them to wonder in the wilderness for 40 years.  People think that fear is the opposite of faith but the Bible shows that walking by sight is the opposite of faith.

Numbers 21:1-9, Numbers 13, Numbers 14, Exodus 13, 2 Corinthians 10:3-6, Numbers 20, Hebrews 11:1