God's Word gives many reasons why we need not fear. Here are a few  reasons.

Shadow—God is with us and will bless us.

Isaiah 43:2
   When thou passest through the waters, I will be with thee; and through the rivers, they shall not overflow thee: when thou walkest through the fire, thou shalt not be burned; neither shall the flame kindle upon thee.

Supplier—God supplies our needs. 

    Philippians 4:19 
 But my God shall supply all your need according to his riches in glory by Christ Jesus.

Strength—The Lord will strengthen and help us in weakness.

Isaiah 41:10 
 Fear thou not; for I am with thee: be not dismayed; for I am thy God: I will strengthen thee; yea, I will help thee; yea, I will uphold thee with the right hand of my righteousness.

Surveillance—God watches over us and cares for us.    Matthew 10:30-31 
 But the very hairs of your head are all numbered. Fear ye not therefore, ye are of more value than many sparrows.

Stumbling—God will not fail or forsake us. 

Hebrews  13: 5
Let your conversation be without covetousness; and be content with such things as ye have: for he hath said, I will never leave thee, nor forsake thee.
Side—God is on our side.

Psalm 118:6
 The LORD is on my side; I will not fear: what can man do unto me?