Seeds begin as a very small object or device, just like our courage. We only need a tiny little seed of courage for it to grow, and once you give that little courage it continues to grow.
Alliteration focuses readers attention on a particular section of text. Alliterative sounds create rhythm and mood and can have particular connotations. For example, repetition of the "s" sound often suggests a snake-like quality, implying slyness and danger.