In the "Introduction" to Songs of Innocence and Experience, the poet meets a small child sitting on a cloud. The child is laughing, but he also means business and starts giving orders to the poet:
Pipe a song about a Lamb; So I piped with merry cheer, Piper pipe that song again – So I piped, he wept to hear. (lines 5-8)
We can imagine hearing "The Lamb" accompanied by a flute, preferably while we're wandering through the woods. But Blake also knew a lot about church music, and he even writes a poem about a choir of children in another of the Songs of Innocence, titled "Holy Thursday." With its easy rhymes, consistent trochaic rhythm, and clear, uplifting subject matter (see "Form and Meter" for more), "The Lamb" sounds like something you might hear sung in a church. Above all, the Songs of Innocence and Experience are meant to be heard by children, or at least the young at heart.