Teaching is a matter of the heart. 

The heart is a hard-working muscle. It pumps blood throughout your body, all day and all night, and that blood provides the things you need and carries away the things you don't need.  So how is teaching a matter of the heart? A teacher never stops. Long after the final bell rings, teachers are tutoring, mentoring, grading, and planning. Teachers provide the material students need to learn and grow and mentor students to help them get rid of the things they don't need in their lives.