Final answer:
John Proctor and Rebecca Nurse's willingness to die at the end of Act IV suggests a plea for forgiveness.
Step-by-step explanation:
The message suggested by John Proctor and Rebecca Nurse's willingness to die at the end of Act IV is a plea for forgiveness. Both characters choose to sacrifice their lives in order to maintain their integrity and preserve their names. Proctor and Nurse recognize the importance of admitting their mistakes and seeking forgiveness from both society and themselves.