It seems to be part of human nature to fear the unknown.  As a child, it might have been darkness; as an adult it may be any unfamiliar event or task that is in our future.  Jesus addresses the Twelve as a parent might console a child.  He encourages his followers to put their trust in his word and in his friendship for them.  He assures them that the Father’s love is as tender as that for a sparrow, and as deliberate as knowing the number of hairs on their head.  Strange comparisons, but we are that precious in the sight of God.