I think Jesus wanted to expose the central issue behind our fear: We don't know God's love for us. If we think God will be disappointed if we rush out ahead and fall down, we're unlikely to move very much.
But if He's your good father, won't he scamper up behind you, giggle a little at your daring, pick you up and brush you off? Then place your feet somewhere more suited to your skill level?
Doesn't it feel better to believe that about him?