Why hasn't John told the court what he knows, what does Elizabeth attribute his not telling to? it is in the second act
John is reluctant to tell the court what he knows, that Abigail is a fraud. He does not want his indiscretions with her revealed.
Elizabeth pleads with him: "The Deputy Governor promise hangin' if they'll not confess, John. The town's gone wild, I think. She (Mary Warren) speak of Abigail, and I though she were a saint, to hear her. Abigail brings the other girls into the court, where she walks the crowd will part like the sea for Israel. And folks are brough before them, and if they scream and howl and fall on the floor, the person's clapped in the jail for bewtichin' them.
Proctor (wide-eyed): Oh, it is black mischief.
Elizabeth: I think you must go to Salem, John. (He turns to her). I think so. You must tell thm it is a fraud.
John is none to quick to do the right thing. His response to Elizabeth is, "I'll think on it."