“The wisdom of the prudent is to understand his way; but the folly of fools is deceit.”—Prov. 14:8.

This proverb teaches us that true wisdom is of a useful or practical nature. There is a great difference between the wisdom of some worldly men and that of others. Some deal in mere speculation; their discoveries are of no use either to themselves or mankind. Others, who are of a more prudent turn, bend their talents to useful purposes. The philosophy of a Lunardi exhibits an air balloon—that of a Franklin is applied to objects of real utility.

But Solomon seldom, if ever, writes of mere natural wisdom. That on which he chiefly dwells has its origin in “the fear of the Lord,” chap. 1:7. The passage may, therefore, be considered as giving the character of holy wisdom, as distinguished from the wisdom of this world; it directs to the understanding of our way, in matters of the highest importance. And this is the proper opposite of the folly described in the last clause, which is said to be deceit. Wicked men are the greatest fools in God’s account; and their folly consists in self-deception. While the wisdom of the truly wise turns to a good account, the folly of the wicked puts a cheat upon their souls.

The wisdom of some men is to understand things which cannot be understood. When David appealed to God, saying, “Lord, my heart is not haughty, nor mine eyes lofty; neither do I exercise myself in great matters, or in things too high for me”—“My soul is as a weaned child”—it implies that there were men who did, and so there are still. “Man,” says Locke, “should know the length of his tether.” What a deluge of abstract speculations has been poured upon the world in all ages, especially since the invention of printing! There is no end to questions upon such subjects. Instead of finding out truth, we presently lose ourselves. Ask, What is a spirit? What is eternity? What is immensity? How came a pure creature to become sinful? Why did God create man, seeing what part he would act? All these, and a thousand more questions of the kind, belong to the wisdom of the imprudent. It does not lead us a step towards heaven, but in a contrary direction.

Again, The wisdom of others is to pry into things which, if understood, are of little or no use.—Long and elaborate treatises have been written on the question, What is space? But cui bono? Even those things which are of use, (astronomy, for instance,) if pursued to the neglect of our way, are folly, and will deceive the expectation. We should blame any man, and count him a fool, notwithstanding his learning, if he employed himself in studying the distances of the stars while his family were pining for want, and his affairs going to ruin; and why not if in the same pursuits he neglects the salvation of his soul?

Further, The wisdom of some is to understand the way of other men.—We meet with many who are exceedingly censorious on public measures. For their part, they are wise; and happy would it be for the world if it were under their direction! but whether it be that the affairs of religious and domestic duty are too little for their expanded minds, or whatever be the reason, so it is, that their own concerns are generally neglected. We meet with others who understand all the private concerns of a neighbourhood, and can point out the faults and defects of every one about them, but forget their own. We have even met with professors of religion, who understand the faults, defects, and errors of almost all the religious world, and, whenever they meet together, these are the topics of conversation by which they edify one another. Surely this is not “the wisdom of the prudent!”

But, it will be asked, what is “the wisdom of the prudent?” And I may answer, It is that which leads to the understanding of our way through life, and to the heavenly home.

Particularly, It will lead us above all things to see that our way be right. There are many by-ways, and many who are walking in them; but true wisdom will not rest till it find out the road that leads to everlasting life. It will know whom it trusts, and whether he be able to keep that which is committed to him. It will lead us also to attend diligently to the directions of the way. We shall read the oracles of God: the doctrines for belief, and the precepts for practice; and shall thus learn to cleanse our way by taking heed thereto, according to God’s word. It will moreover induce us to guard against the dangers of the way. We shall not be ignorant of Satan’s devices, nor of the numerous temptations to which our age, times, circumstances, and propensities expose us. It will influence us to keep our eye upon the end of the way. A foolish man will go that way in which he finds most company, or can go most at his ease; but wisdom will ask, “What shall I do in the end thereof?” To understand the end of the wrong way will deter; but to keep our eye upon that of the right will attract. Christ himself kept sight of the joy that was set before him. Finally, as holy wisdom possesses the soul with a sense of propriety at all times, and upon all occasions, it is therefore our highest interest to obtain this wisdom, and to cultivate it by reading, meditation, prayer, and every appointed means. “My son, if thou wilt receive my words, and hide my commandments with thee, so that thou incline thine ear unto wisdom, and apply thine heart to understanding; yea, if thou criest after knowledge, and liftest up thy voice for understanding; if thou seekest her as silver, and searchest for her as for hid treasures; then shalt thou understand the fear of the Lord, and find the knowledge of God. For the Lord giveth wisdom; out of his mouth cometh knowledge and understanding. He layeth up sound wisdom for the righteous; he is a buckler to them that walk uprightly.”

Fuller, A. G. (1988). “True Wisdom,” Sermon LVII. The Complete Works of Andrew Fuller: Memoirs, Sermons, Etc. (J. Belcher, Ed.; Vol. 1, pp. 464–466). Sprinkle Publications.