Think not to say within yourself, “No one can know what his heart is. We must hope the best. No one can find out with any certainty the state of his own soul.” Beware, I say again — beware of such thoughts. The thing can be known. The thing can be found out. Deal honestly and fairly with yourself. Set up a ‘trial’ on the state of your inward man. Summon a jury. Let the Bible preside as judge. Bring up the witnesses. Inquire what your tastes are — where your affections are placed — where your treasure is — what you hate most — what you love most — what pleases you most — what grieves you most. Inquire into all those points impartially, and mark what the answers are. “Where your treasure is there will your heart be also.” (Matt. 6:21) A tree may always be known by its fruit, and a true Christian may always be discovered by their habits, tastes, and affections. Yes! you may soon find out what your heart is, if you are honest, sincere, and impartial.
– JC Ryle –