What occurs in Toms dream in William Blake's The Chimney Sweeper?

In William Blake's poem "The Chimney Sweeper," Tom has a dream where an angel sets him and other chimney sweepers free from their oppression and misery. The angel tells them that if they are good and obedient, they will be taken to a place of joy and freedom. This dream offers Tom hope and comfort in his harsh reality as a chimney sweeper.