This excellent poem that makes up part of the Songs of Experience of Blake's most famous work represents some of Blake's harshest critcism of the church and the impact it has. Note how in what used to be a garden, a chapel has been built. This building has managed to transform the garden, which was a place of freedom, into a graveyard.
Some critics argue that the image of the "green" in the garden represents the playing space of childhood, which eventually comes under the dominion of law and order. This represents, it is argued, the way in which the liberty of the state of childhood becomes the restricted and trapped state of being an adult. Blake therefore could be said to be arguing for a world in which that sense of freedom continues into adulthood, rather than "binding" the "joys and desires" of adults.
However, other critics focus on line two and argue that this leads to a crucial ambiguity in how we read the poem:
I went to the Garden of Love,
And saw what I never had seen:
A chapel was built in the midst,
Where I used to play on the green.
Therefore we could argue that this indicates not that the chapel has been recently built, but it was there all along and has only just now been noticed by the speaker. We can either argue that this represents the way that rules and regulations and restrictions gradually emerge as we mature into adults, or we can say that the sudden appearance of the chapel indicates something about the speaker and his sudden insight into the way that religion and other regulations of society actually restrict and take away our freedom and innocence. Either way, it is obvious that adulthood, or the state of "experience" is presented in negative terms, as flowers are replaced with tombstones and the place of play and freedom now has "Thou shalt not" written on the chapel door.