The Chimney Sweeper - William Blake

My interpretation of "The Chimney Sweeper" by William Blake, is a poem about a child sold into slavery at a young age, as the line "my father sold me while yet my tongue could scarcely cry 'weep! weep! weep! weep!'" would indicate. These work conditions, needless to say are not pleasant. To illustrate, the boy talks of "sleeping in soot". Further, he describes his friend and fellow chimney sweeper, Tom, having a grim dream using imagery with words like "coffin". However, Tom's dream seems to translate into a sort-of message of hope. While in the dream, their friends are in a coffin or in other words, dead, an angel with a "bright key" comes and sets them free. Blake, then paints a utopian, heaven-like picture, describing the boys laughing in green fields, washing themselves in the river and sunshine; they leave their bags behind, a symbol of no longer being obliged to the duties of their jobs. The angel then tells Tom, that if he is a "good boy", he too would have this to look forward to in the future. The last line says "so if all do their duty they need not fear harm". To me, this represents a sort-of coming to peace for Tom; he knows that he is going to continue to works this job. However, eventually he will pass on from this life and be relieved of the burdens that currently dominate his life. While it seems to be a message of hope, I also find it to be sad that his only way of being happy and at ease, is through death.