In the context of Matthew 10, Jesus is telling his twelve disciples what to expect when they go from city to city, preaching the gospel. He explains to them that the world will hate them because of the message they preach – including those of their own household (Matthew 10:16-22). He then tells them to preach the whole gospel without fear (Matthew 10:26-27), the only person to fear is the One who can destroy both body and soul in hell (Matthew 10:28).
In Matthew 10:31, He then goes to to say that the disciples are of far more value than that of mere sparrows, therefore, they are not to “fear” what man can do to them – God will take care of them, even in death (Matthew 10:29-31; cf. Romans 8:28-39; cf. Psalm 116:15; Revelation 14:12-13).
When Jesus rides in our boat, there is absolutely nothing to fear: http://mbriley.preachersfiles.com/2010/02/05/when-jesus-rides-in-our-boat-2/