"Spring" is a lyric poem written and illustrated by William Blake.
William Blake's Songs of Innocence (1789) is a lyric anthology that consists of nineteen illuminated poems.
The last line of each stanza is the same to show the joy the author has for this time of year.
There are several reference's to other poems or characters from Blake's "Songs of Innocence."
Together Blake incorporates these characters into a happy poem welcoming Springtime, which marks the beginning of a new year for them.
[3] This format shows the transition from innocence to a bit of romance, where the child and lamb become close.
With only a single word change, going from "to" to "we", representing the growth of the characters, and how they deviate from the "innocent" title given to them.