Yeah at first I was surprised Ben was falling for it, but everything the Adversary said did make sense to him. This guy has been lurking in the shadows for decades ordering Ben around without ever making contact with him. Actually I was fascinated to learn that Ben's contact with him is through Richard who hands him little scrips of paper with instructions and lists of names. Makes you wonder how altruistic Richard is here. Could it be Richard is the one taking actions in Jacob's name?