Reverend Hale is trying to understand the situation he is in. He has been surprised by the accusation against Rebecca Nurse, having accepted her as an intelligent and well-read person, like himself. He isn't sure what to make of the Proctors, and does not understand why they would avoid attending church. It is in this scene that John Proctor speaks out against Rev. Parris, criticizing the man for hypocrisy and explaining his avoidance of church revolves around that, and not his belief or disbelief in God.
Hale still believes in his quest here, especially when he first arrives at the house. However, unlike the townspeople, he has an open mind, and his visit with the Proctors begins to tear at what few doubts he does have. He goes in order to find truth - it just isn't the truth he thought he would find.
Hale goes to the Proctors to warn them to get their religious affairs in order, such as baptizing their youngest child. Elizabeth's name has been brought up by Abigail as a witch, and Hale wants the Proctors to look like they are religious, upstanding people. He has them recite the Ten Commandments, and John Proctor forgets the one about adultery. He tells them to make sure they go to church from now on and to do whatever they're supposed to as good Puritans. He doesn't want Abigail or any of the others to have a good reason for calling either of them a witch.
At this point, Rev. Hale realizes the witch trials are fake, and he wants to save anymore people from prison or from being hanged. He goes to the Proctors to help them.