Mark 6:50
"For they all saw him, and were troubled. And immediately he talked with them, and saith unto them, Be of good cheer: it is I; be not afraid."
Cross References (ranked by relevance)
Matthew 14:27
11
But straightway Jesus spake unto them, saying, Be of good cheer; it is I; be not afraid.
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.