This happy poem draws together several of the images from throughout the Songs of Innocence, all so that they can “Merrily Merrily…welcome in the Year.” The flute from the Introduction, both Day and Night from several poems, the Little Boy from “Little Boy Lost” and “Little Boy Found,” and the lamb from “The Lamb” all make an appearance in this simple poem celebrating life in springtime.
In every case, those addressed come "Merrily merrily to welcome in the Year." Blake's new year begins in springtime, when life itself is renewed throughout nature. The birds and the flautist, who is presumably the Shepherd from the first two poems, being by singing in the new year. Then the little boy and girl playfully cheer on the spring, similar to the image of children at play in "The Ecchoing Green." Finally the lamb, a symbol both of innocence and of the person of Christ, comes to "lick /My white neck" and be kissed in turn by the speaker, indicating the soul's response to God's love as revealed in the natural world.
"Spring" has three stanzas. Each stanza is nine lines long and has the rhyme scheme AABBCCDDE. Structurally, each line of "Spring" gets progressively shorter in visual appearance while maintaining a three-syllable line in each instance. The exception here is the last line of each stanza, which extends to twelve syllables, which is exactly half the length of the previous eight lines combined. In fact, line 9 is also unusual in that the first half of the line is merely the repetition of line 8, "Merrily," and ending with "to welcome in the Year." This line, repeated at the end of each stanza, acts as a refrain that gives the poem a songlike quality as the speakers welcome in the new season of life.