He who does not improve his temper together with his understanding, is not much the better for it. - Basil John Mason

[Scripture], by which, “as in a glass, we may survey ourselves, and know what manner of persons we are,” (James 1. 23) discovers ourselves to us; pierces into the inmost recesses of the mind; strips off every disguise; lays open the inward part; makes a strict scrutiny into the very soul and spirit; and critically judges of the thoughts and intents of the heart. (Heb. iv. 12) It shows us with what exactness and care we are to search and try our spirits, examine ourselves, and watch our ways, and keep our hearts, in order to acquire this important self-science; which it often calls us to do. “Examine yourselves; prove your own selves; know you not yourselves? Let a man examine himself.” (1 Cor. xi. 28) Our Saviour upbraids his disciples with their self-ignorance, in not “knowing what manner of spirits they were of.” (Luke ix. 55) And, saith the apostle, “If a man (through self-ignorance) thinketh himself to be something, when he is nothing, he deceiveth himself. But let every man prove his work, and then shall he have rejoicing in himself, and not another.” (Gal. vi. 3, 4) Here we are commanded, instead of judging others, to judge ourselves; and to avoid the .inexcusable rashness of condemning others for the very crimes we ourselves are guilty of, (Rom. ii. 1, 21, 22) which a self-ignorant man is very apt to do; nay, to be more offended at a small blemish in another's character, than at a greater in his own; which folly, self-ignorance, and hypocrisy, our Saviour, with just severity, animadverts upon. (Mat. vii. 3-5) And what stress was laid upon this under the Old Testament dispensation appears sufficiently from those expressions. "Keep thy heart with all diligence." (Prov. iv. 23) "Commune with your own heart." (Psal. iv. 4) "Search me, O God, and know my heart; try me, and know my thoughts." (Psal. cxxxix. 23) "Examine me, O Lord, and prove me; try my reins and my heart." (Psal. xxvi. 2) "Let us search and try our ways." (Lam. iii. 4) "Recollect, recollect yourselves, O "nation not desired." (Zeph. ii. 1)

Other sciences are suited to the various conditions of life: some, more necessary to some; other, to others. But this [science of self-knowledge] equally concerns every one.

Thales, the Milesian, is said to be the first author of it1; who used to say, that, for a man to know himself, is the hardest thing in the world2. It was afterwards adopted by Chylon the Lacedemonian; and is one of those three precepts which Pliny affirms to have been consecrated at Delphos in golden letters. It was afterwards greatly admired, and frequently used by others1; till at length it acquired the authority of a divine oracle; and was supposed to have been given originally by Apollo himself. Of which general opinion Cicero gives us this reason; "because it hath such a weight of sense and wisdom in it, as appears too great to be attributed to any man*." And this opinion, of its coming originally from Apollo himself, perhaps was the reason that it was written in golden capitals over the door of his temple at Delphos.