Foreshadowing!

"'Are you guilty?' said Winston.
'Of course I'm guilty!' cried Parsons with a servile glance at the telescreen. 'You don't think the Party would arrest an innocent man, do you?'" -page 233

This quote shows us just a glance about what is to become of Winston. At the time both Winston and the reader (for the most part) is unaware that this man could very well be innocent and just brainwashed by the party. He thinks that it is simply ludicrous that anyone would question the rightness of the party even though we can only assume that is exactly what Parsons did to get caught in the first place. In fact, at the time Parsons probably knew full and well that the party didn't like whatever it was he was doing but in his own conscience saw nothing wrong with it. Woah! That's exactly like Winston! So basically I think this quick little chat between Parsons and Winston is a bit of a preview of what Winston is to become!