In the beginning of Act Two, we see a very strained and awkward Elizabeth and John communicating. It is obvious that they are still trying very hard to put their marriage back together after John's affair with Abigail. And, some time has passed since Act One, where the girls first starting crying out people as witches. Mary Warren, a servant in the Proctor household, has been going to town every day, and brings back reports of how crazy and chaotic things have gotten. Elizabeth tells John,
"There be fourteen people in the jail now...and they'll be tried, and the court have power to hang them too...if they'll not confess."
It is hard to believe that in their little town such chaos and death is possible. John had told Elizabeth that Abby had told him that there was no witchcraft involved--that Betsy "took fright is all." It is a pretty significant thing that Abby told John--she is basically saying that witchcraft had nothing to do with anything. And, now that she is one of the main "accusers" of witchcraft, people believe her, and people are going to be hanged as a result. Elizabeth wants John to go to town and tell people what Abby had told him, that "it had naught to do with witchcraft." She is hoping that they can prove Abby a liar, and then all of the innocent men and women will be released from jail.
So, in a nutshell, Elizabeth wants John to go into town and tell everyone there that Abby told him that there was no witchcraft involved at all; hopefully, that would prove Abby a liar, and lives could be saved. I hope that helps; good luck!