Kind of an oxymoron? Marriage can be related to the ideals of life, and hearse is related to death.

Here, there is the contrast of innocent chimney sweepers being placed in dangerous work positions by family and institutions, while those same people go to church and pray for their sins.

The repetition of "charter'd" reminds me of the feelings of ownership, a sense of having control vs losing control. The speaker is setting the tone of individualism vs industrialization.