John Gill Bible Commentary

They are all plain to him that understandeth,.... Whose understanding is enlightened by the Spirit of God; who is a spiritual man, that has a discerning, and can judge of spiritual things: as for the carnal man, let him have what natural knowledge or wisdom he will, he cannot know these things; for they are spiritually discerned, and can only be discerned by spiritual men. The Bible is a sealed book to others, learned or unlearned; the mysteries or doctrines of the Gospel are hid in parables from such; but those to whom Christ has given an understanding to know him, these know them, and they are plain unto them: for though there are some things hard to he understood in the Scriptures, as in Paul's epistles, and some sublime truths in the Gospel; yet those which are necessary to salvation are easily understood; that faithful saying, and worthy of all acceptation, that Jesus Christ came into the world to save the chief of sinners, is a very plain one; and right to them that find knowledge; a spiritual and experimental knowledge of Christ and his truths. The Targum is, "to them who desire knowledge;'' and so the Syriac version; that seek for it heartily and diligently, in a right way, in the use of proper means, under the direction and by the assistance of the Spirit of God.