Herein is my Father glorified, that you bear much fruit; so shall you be my disciples.
It is indeed true, and a truth never to be forgotten, that all pretensions to internal princples of holiness are vain when they are contradicted by our conduct; but it is no less true, that the only effectual way of improving the latter, is a by a vigilant attention to the former. It was therefore our blessed Saviour's injunction, "Make the tree good" as the necessary means of obtaining good fruit; and the Holy Scriptures abound in admonitions, to make it our chief business to clutivate our hearts with all diligence, to examine into their state with impartiality, and watch over them with continual care. Indeed it is the heart which constitutes the man.
-William Wilberforce (A Practical View of Christianity)