believing and doing: how do they stack up?

There's been some ongoing discussion all over the place about statements of truth and commands to obey in scripture (indicatives and imperatives).

I found Kevin deYoung's latest piece a helpful response, especially his answer to the question, "Should Christians be exhorted to obey the imperatives or does sanctification so invariably flow from justification that the way to get obedience is always and only to bring people back to the gospel?"

(Clue: the answer is 'yes, they should' because 'no, it doesn't and it isn't')