The narrator tells of his visit to the Garden of Love and of the chapel standing where he played as a child. Instead of welcoming him in, the chapel has the negative 'Thou shalt not' of the Ten Commandments written over the door. The narrator sees that this negative morality has blighted the garden as well, reducing the 'sweet flowers' to graves and tombstones. The mechanical ritual of the priests 'walking their rounds' threatens to choke out the narrator's life itself.

The key to the poem lies in its second line. The narrator is talking about the change in how he now sees his surroundings, not a change in the garden itself. The poem is central to Blake's design in the Songs of Experience, as it marks the psychological passage from childhood innocence to adult experience. There are strong echoes of the passage from innocence to knowledge of Adam and Eve in the Garden of Eden. Just as their tasting the apple has commonly been interpreted as a sexual awakening, so too the narrator's 'joys and desires' include the physical pleasures he is denied by the rule-bound morality of the church. The last two lines, with their heightened metre and rhyme pattern, sum up what Blake saw as the threat of losing the 'joys and desires' of childhood innocence: unless we can develop our creative imagination to replace that lost innocence, we will lose the essence of life itself.
In this poem, Blake may also be attacking a new chapel built in Lambeth near his then home. This chapel was built by subscription: parishioners paid for their pews. Blake was appalled at the idea that those who could not pay would be excluded from Christianity's 'Garden of Love'.