Do not be afraid. This is a common theme in the Scriptures. It is God's constant word to us. Instead of being afraid we are called to trust in the Lord's divine providence for us, his plan for our life. We are not talking about natural, human fear. Like I am afraid of snakes. What God is talking about is not to fear the power of evil or the things that come from evil. Or we are called not to be afraid to act on the word of God to us in a given situation. Instead of fear, we are invited to stand firm in our relationship with God. The greater our trust in God, the less will fear have control over us. As long as Peter kept his eyes on Jesus, he was able to do the impossible, walk on the water. But as soon as took his eyes off Jesus and looked at the menace of the sea, he began to sink. What am I afraid of? What is the source of my fear? What does Jesus want me to do to overcome my fear? 

Reflect on this passage from St. Paul. "No, in all these things we conquer overwhelmingly through him who loved us. For I am convinced that neither death, nor life, nor angels, nor principalities, nor present things, nor future things, nor powers, nor height, nor depth, nor any other creature will be able to separate us from the love of God in Christ Jesus our Lord" (Romans 8:37-39)