I read several stories on this to try and get more info. So far from what I've seen:
1) The usual MSM outlets are using headlines with "resist" in them for, you know...
2) If you read into what he says, he's simply saying that if Trump (or any president) gave an order that could be illegal (most likely unknowingly), the staff with all the stars and bars are there to tell them, "Wait, I don't think we can do that." I'm paraphrasing his quote in one article that basically states, " I would tell the president that could be illegal. The president would ask me for my advice on how to react legally, and I would give him that advice. That's how it works." The whole "Trump" and "resist" stuff is just the fake news pushing a bias.