Taking the easy route is not always (or usually?) the correct one. It is easy to teach the first idea that comes into our head, but we need the Spirit and the correction of one another to teach what God wants. It is easy to chase our own needs, but we should instead deny the short-term for the better things of eternity. This is the focus teachers must keep both for themselves and for those they intend to teach, and Paul wants Timothy to remember that.