The Heart

The hypocrite's only care is to keep his outward life
from defilement. But the sincere Christian's care is mainly
to keep his heart from defilement; for he very well knows,
that if he can but keep his heart clean--he shall with more
ease keep his life clean. If the fountain is kept pure--the
streams will run pure. The heart is the spring of all actions,
and therefore every action is as the spring is, from whence
it flows; if the spring is good--the action is good which flows
from it; if the spring is evil, the action is evil which flows
from it.

From Grace Gems
(Thomas Brooks, "A Cabinet of Choice Jewels" 1669)