Final answer:
Parris is worried that if Rebecca Nurse prays on the gibbet before her execution, her perceived martyrdom could inspire others to seek vengeance on the judges and authorities.
Step-by-step explanation:
The speaker, Parris, is expressing concern that if Rebecca Nurse stands upon the gibbet and prays, her righteous demeanor and the reverence she commands might incite vengeance upon the judge and those responsible for executing her.
He is indicating that Rebecca Nurse is highly respected, and her execution, especially if she appears pious and innocent in her final moments, could turn public opinion against the court and lead to retaliation or unrest. The people might see her martyrdom as an injustice, prompting them to take action against the judicial authorities.