Have you ever spent time to consider what values your kids are learning from you? Sometimes it's helpful to take a step back and really examine, what are the kids learning from my behavior?
Kids learn way more from what they see you do rather than what they hear you say. So, if you tell them, "It's important to be generous and give to others in need," but they don't ever see you volunteer any time or money to others, your words aren't going to sink in. Or, if you tell kids that family is the most important thing in the world but they see you come home from work and spend your evenings cleaning the house instead of spending family time together, they'll learn that work is more important.
If you're like most parents, you probably haven't spent much time really thinking about what your values are and how you are passing those values onto your kids. It can be a humbling experience to really think about what sorts of things your might be teaching your kids without really meaning to.
There's an excellent book called "When You Say 'Thank You,' Mean It." It is about the importance of really teaching kids values. It provides lesson plans to help parents teach and instill values in their kids.