After John Proctor confesses, what does Danforth want him to do?

In Arthur Miller's "The Crucible," Danforth tells John Proctor he must sign a letter of confession. This letter is going to be posted on the church door so the whole town can see what Proctor has done.

Danforth says the reason for this signed confession is so he can use Proctor as a kind of instructional lesson for others who are dealing in witchcraft or know someone who is dabbling in witchcraft. Proctor initially goes along with Danforth's instructions but has second thoughts. Proctor tears up the confession and says it would go against everything he stands for if he allowed the letter to continue to exist.