This is the wisdom of 1 Corinthians 15:33. We know it instinctively, and we also know that the corollary is also true: Good company will build good morals.
Great Christian educators build a Biblical worldview in their students. They teach their children that they are on this earth to bring glory to God, not to enrich themselves for their own purposes. They do this in many ways, but one thing is for sure. Their subjects are not only about the what, it is also about the why and how they are teaching those subjects.