Can you please explain the importance of the follwing quote from Bless Me, Ultima?
"They will burn sulfur instead of holy incense. They will sing and dance around her coffin, pulling at their hair and flesh. They will slay a rooster and spread his blood on their dead sister" (Anaya 139).
When Tenorio Trementina's first daughter dies, the town of El Puerto begins to gossip about the family. Many people believe that the daughters are witches.
According to Tony’s uncle, Tenorio’s wife “made many people of the valley sick, some died from her curses. She paid for her sins, but not before she delivered three brujas [witches] to carry on her work.”
In the passage quoted in the question, the details refer to witchcraft. The people of the town are contrasting the (supposed) practices of the Trementina family with normal and/or Christian burial practices.
The burial rites described here are occult, related to devil worship and/or witchcraft.
The Trementina family proves later that they do practice witchcraft. Symbolically and literally, Ultima stands in opposition to these practices. Also, the priest in El Puerto stands against the Trementina family, disallowing any burial of the dead daughter on sacred church ground.