The heart of him that hath understanding seeketh knowledge,
&c.] He that has in his heart an understanding of divine and spiritual things, of the Gospel and of the truths of it, will seek earnestly and diligently in the use of proper means after more knowledge; as he will desire to know more of Christ, his person, offices, and grace, he will follow on to know him, and not be content with the present degree of knowledge he has attained unto; he will hear and read the word, and pray and meditate, in order to come to a more perfect knowledge of the son of God, and of those things which relate to his spiritual peace and eternal welfare; but the mouth of fools feedeth on foolishness;
on foolish talking and jesting; on foolish and unlearned questions; on foolish and false doctrines; on foolish and hurtful lusts; on wind and ashes, a deceived heart having turned them aside: they take pleasure and satisfaction in those things; feed their fancy with them and feast upon them, which shows what fools they are; and such all unregenerate men be.