The fear of the LORD is the beginning of knowledge: but fools despise wisdom and instruction. The fear of the Lord - In the preceding verses Solomon shows the advantage of acting according to the dictates of wisdom; in the following verses he shows the danger of acting contrary to them. The fear of the Lord signifies that religious reverence which every intelligent being owes to his Creator; and is often used to express the whole of religion, as we have frequently had occasion to remark in different places. But what is religion? The love of God, and the love of man; the former producing all obedience to the Divine will; the latter, every act of benevolence to one's fellows. The love of God shed abroad in the heart by the Holy Spirit produces the deepest religious reverence, genuine piety, and cheerful obedience. To love one's neighbor as himself is the second great commandment; and as love worketh no ill to one's neighbor, therefore it is said to be the fulfilling of the law. Without love, there is no obedience; without reverence, there is neither caution, consistent conduct, nor perseverance in righteousness.
This fear or religious reverence is said to be the beginning of knowledge; ראשית reshith, the principle, the first moving influence, begotten in a tender conscience by the Spirit of God. No man can ever become truly wise, who does not begin with God, the fountain of knowledge; and he whose mind is influenced by the fear and love of God will learn more in a month than others will in a year.
Fools despise - אוילים evilim, evil men. Men of bad hearts, bad heads, and bad ways.