| Quote #1 Because I was happy upon the heath |
The chimney sweeper says he was "happy upon the heath"; a heath is a wide open space, associated with wildness and freedom. So, for this kid, happiness is freedom to frolic. But now that the kid's no longer free, he can't be happy, right?
| Quote #2 And because I am happy and dance and sing, |
Happiness is here again close to sadness; the chimney sweeper says he sings, but remember, he sings notes of woe. So is he really happy? Or does he just sound happy, if you're not paying attention?
| Quote #3 And are gone to praise God and his priest and king, |
The phrase "make up a heaven of our misery" suggests that happiness is often a product of sadness; "God, and his priest and king" can only make themselves a heaven, after all, if they have the child's misery.