We don't trust people to follow the rules, we trust them to know when to break them.
- Simon Sinek, Talks at Google
A big part of me is always skeptical of most business "gurus" as some sort of snake oil salesmen (if you have the secret to business success, why aren't you Bill Gates or whomever?).
However, I think Sinek - along with four or five others - who approach the business field (whether profit or nonprofit) as an arena to be studied and analyzed are worth bearing in mind.
Sinek's insights on culture are equally applicable to for-profit and non-profit companies - because ultimately we want the best people focused on our why. So I encourage you to watch his google talk referenced above or to check out his better known talk on Starting with the Why.