By Pastor Dr. Ronnie W. Wolfe
Skeptics will say that the word "vain" is not in the Hebrew language, but we must realize that the thought of vanity is mentioned many times in the Old Testament. Exodus 5:9 and Job 16:3 speak of "vain words," "vain men" in 2 Chron. 13:7 and Job 11:11, and "vain persons" in Psalm 26:4. See also Jeremiah 4:14.
Also, the fact that the end of this verse speaks in contradiction to the thoughts of the first part of the verse as "thy law" strengthens the idea that the word "vain" should be used.
Jesus spoke about vanity in Matt. 15:9 But in vain they do worship me, teaching for doctrines the commandments of men. Vain doctrine is vain thought. There are many warnings about false teachers and false doctrine from the apostles.
We should always be on the alert for false doctrine, since doctrine is extremely important to our Christian view of things. When compared to the law of God (the Bible), these thoughts can be quickly recognized, these doctrines can be identified and cleansed from our thoughts.