“Do not fear; only believe” is the command of protection, the voice of encouragement, the sound of salvation and of course the voice of Jesus when He came to this earth to remove the fear from our hearts and fill us with His faith and eternal life. In Mark 5:35-43, we read how Jesus performed a tremendous miracle.
Just Believe simply means to walk by faith, not by sight. We are not to look behind, nor are we to look ahead as far as we can see.
Mark 5:36 New King James Version (NKJV)
As soon as Jesus heard the word that was spoken, He said to the ruler of the synagogue, “Do not be afraid; only believe.”