What does the Bible say about vanity? What is it? Why is it something to be avoided?
A secular definition of vanity is having an excessive pride in one’s looks, appearance, status, or abilities compared to that of others. The word vain comes from vanity and someone who is vain has the quality or character of being conceited, narcissistic (in love with self), and sees themselves as superior to all others, regardless of their real status in life. You see a lot of vanity in today’s professional athletes (not in all of them) and those with high-paying jobs who wield much power, prestige, and influence over others. Some see vanity more in Hollywood than in any other place or industry but vanity is spread throughout the entire world in TV, movies, magazines, newspapers, and over the Internet. You can see vanity walking down the sidewalk or in the way someone acts or talks to others as in talking condescendingly down to others. God is opposed to those who are full of themselves (James 4:6) and act in a vain way toward anyone else. The biblical definition of vanity or the word vain is “empty, useless” or “nothing” as we will later see as this is evidenced by Jesus’ statement to the hypocritical religious leader’s worship of God.
Solomon and Vanity
Solomon wrote more about vanity than anyone else in the Bible and the word vanity is found in Ecclesiastes  more than in all the other books in the Bible combined. Perhaps because Solomon had so much wisdom, had everything he ever wanted, and was at the height of power, he personally knew a lot about vanity from experience but he apparently humbled himself later (actually God did it for him) and so that is why he know so much about vanity as we will read from his many writings found in what is called the wisdom literature, primarily in Ecclesiastes although it is found elsewhere.
Ecclesiastes 1:14 “I have seen all the works which have been done under the sun, and behold, all is vanity and striving after wind.”
Solomon describes vanity as works done here on earth and in the end, it basically comes to nothing. As he writes it’s like “striving after wind” or trying to grab hold of the wind. I would say it like this; “It’s like trying to nail Jell-O to the wall.”
Ecclesiastes 2:11 “Thus I considered all my activities which my hands had done and the labor which I had exerted, and behold all was vanity and striving after wind and there was no profit under the sun.”
If you look at anything we do with our hands there is no real profit in the end which reminds me of what Jesus said “For what shall it profit a man, if he shall gain the whole world, and lose his own soul” (Mark 8:36)?
Ecclesiastes 2:15 “Then I said to myself, “As is the fate of the fool, it will also befall me. Why then have I been extremely wise?” So I said to myself, “This too is vanity.”
Both the fool and the wise end up in the same place so everything done outside of the wisdom of God will simply come to nothing. Here is true wisdom; fear God because that’s the beginning of wisdom (Psalm 111:10).
Ecclesiastes 4:4 “I have seen that every labor and every skill which is done is the result of rivalry between a man and his neighbor. This too is vanity and striving after wind.”
Rivalry is certainly motivated by pride or vanity. If there is rivalry between neighbors, there you will find sin. Rivalry can be the coveting of a neighbor’s goods or even his wife or her husband. Where there is rivalry there is always pride.
Worshiping God in Vain (or in vanity)
Jesus told the woman of Samaria at the well that “an hour is coming, and now is, when the true worshipers will worship the Father in spirit and truth; for such people the Father seeks to be His worshipers. God is spirit, and those who worship Him must worship in spirit and truth” (John 4:23-24). Jesus had previously told the woman “You worship what you do not know; we worship what we know” (John 4:22) so apparently we can worship God in the wrong way. This is why Jesus rebuked the scribes and the Pharisees “You hypocrites, rightly did Isaiah prophesy of you: This people honors Me with their lips, But their heart is far away from Me, But in vain do they worship Me, Teaching as doctrines the precepts of men” (Matt 15:7-9). Jesus was quoting one of His favorite books to quote and in this case, Isaiah 29:13.
Even Christians can worship God in vain, meaning in a useless, empty way. Without the adoration of God and the awe of His magnificence, we are just going through the motions and it means nothing to God and as we have already read, empty or useless worship is all vanity. Jesus told the woman at the well that the Father is seeking such to worship Him in spirit and in truth. That means in a humble, contrite, broken spirit and in truth; biblical truth and anything besides this is all vanity. Remember that Jesus told the woman at the well “You worship what you do not know” because she didn’t really know God and didn’t know the Messiah (Jesus) but I was like that woman for a very long time. The scribes and the Pharisees were worshiping God  in vain because they had heaped up their own traditions (which is not truth) and boasted of their own righteousness (not in the right spirit). Their doctrines were not biblical truth, they were the “traditions of men” and what was even worse, they made their traditions at least equal too but really superior over the laws of God. The laws were to honor their father and their mother but they weren’t obviously doing that (Matt 15:4) but they were following their own traditions, superseding the laws of God (the 5th Commandment) and neglecting their own parents (Matt 15:5-6).
We all have it in us to be vain and be full of vanity. It is within our fallen nature but when God gives us His Spirit, He gives us a new heart, not one of stone but of flesh (Ezk 36:26). God’s Spirit changes our hearts…we get a heart transplant…one that is bent toward pleasing God, toward obeying Him, and worshiping Him in spirit and in truth. In doing so, it is not done in vanity or vain. As Jesus said of the Father, it is “for such people the Father seeks to be His worshipers.”
Here is something else that might interest you: 10 Idols of Your Heart to Remove 
Resource – Scripture quotations are from The Holy Bible, English Standard Version® (ESV®), copyright © 2001 by Crossway, a publishing ministry of Good News Publishers. Used by permission. All rights reserved.