I. We may take these words of the Book of Proverbs as a warning to seek self-knowledge. And, as a first step to self-knowledge, they bid us beware of trusting our own heart, or we shall but see ourselves, in a high moral sense, to be "fools" at last. But it may be asked, Is not the heart God's creation and God's gift? Did He not plant eyes in it and give to it; light and discernment to guide our ways? Why must a man who trusts his own heart be a fool? (1) Because our hearts that is, we ourselves are ignorant of ourselves. If we knew ourselves, we should not trust ourselves; we do so because we do not know what we are. (2) Not only is the heart ignorant of itself, but it deceives itself. Ignorance is the danger of unawakened minds, self-deceit of the awakened. (3) Another reason why to trust our own hearts is a note of folly is because they flatter us. Self-flattery imposes upon us with the conceit of our own excellence.
II. If this be so, if we be our own deceivers, what securities shall we take against our own hearts? Out of many we can now take only two. (1) The greatest security against deceiving ourselves by trusting our own hearts is a careful information of conscience. A knowledge of sin in itself would interpret to us the true moral character of our own conduct and all its intricate parts of thought, word, and deed. Another benefit of this early information of conscience is that we should be preserved from the stunning and deadening insensibility which early sins bring upon us. No words too strong can be found to urge on parents and guides of children to begin the information of the conscience as early as the information of the reason. (2) The other security is the only one which remains to those who have never enjoyed the first, and that is to take the judgment of some other person instead of trusting in themselves. We advise others better than ourselves; so would they us again. How little do we lay to heart who he is that would fain stop our ears against all advisers. And the man who takes counsel of nobody is his easy prey.
H. E. Manning, Sermons,vol. iii., p. 92.
References: Proverbs 29:15. New Manual of Sunday-school Addresses.p. 164.Proverbs 29:1. Preacher's Monthly,vol. iii., p. 359; Clergyman's Magazine,vol. x., p. 84; J. Keble, Sermons for Saints' Days,p. 174.Proverbs 29:1-11. R. Wardlaw, Lectures on Proverbs,vol. iii., p. 285.Proverbs 29:12-18. Ibid.,p. 297. Proverbs 29:15. Outline Sermons to Children,p. 77.