Even though I walk through the valley of the shadow of death, I will fear no evil, for you are with me, your rod and your staff they comfort me. – Psalm 23:4
Fear often stands in the way of our faith. When we are looking around envisioning only the bad things that might happen and becoming afraid — that is when our trust disappears into doubts.
Evil can mean many things here. It might be the actual presence of evil, it could be calamity or pain, it might even be our own falling into temptations. Regardless, God is with us, and with us in a powerful way.
Notice that walking through the valley is not necessarily because we have strayed. Difficult circumstances often come and this is where the path leads. Our natural reaction is apprehension and fear, we are inclined to run or try to fight through the situation on our own. Instead we have to give in to faith, believing that Jesus our shepherd is right in front of us leading the way.
Anything we are going through, the darkest path through the darkest valley, He is with us. We hold onto Him, and keep our eyes upon Him. We keep listening to His voice. We stop looking at the darkness and the evil, and thinking about all the bad things that might happen. We follow Jesus. That is how our fear turns back to faith.