The Vanity of your mind;?

Where is your focus? 

 Worry, fear, fear, unbelief, and anger all come out of the heart!

 " For from within, out of the heart of men, proceed evil thoughts, adulteries, fornication's, murders, thefts, covetousness, wickedness, deceit, lascivious, an evil eye, blasphemy, pride and foolishness. "    -  Mark 7:21,22 

If these are the products of your heart!  Then when responding in this way;  your understandings will become darkened and you will become insensitive to the True Word of God in your life.

Therefore you must learn to  - 
 " Let the peace of the Lord God rule in your hearts. "  -  Colossians 3:15

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Once you come to walk in the vanity of your mind; it darkens your understanding / imagination.    
 Vanity of a person is seen as having excessive estimation (over estimation) of one’s self, abilities, looks, or other attributes that makes them have an excessive belief in their own abilities or attractiveness to others.

Mankind’s Teachings in Vain(wasted energy)

There is also something that is vanity or done in vain and that is teaching manmade religious rules. 

- Jesus rebuked the religious leaders of His day saying

 “in vain do they worship me, teaching as doctrines the commandments of men” 

(Matt 15:9). 

- Elsewhere Jesus said they 

“leave the commandment of God and hold to the tradition of men” (Mark 7:8). 

- The commandments of mankind are flawed but the law of God is perfect and only it can convert the soul (Psalm 19:7). This is Paul’s reason for

 “holding fast to the word of life, so that in the day of Christ I may be proud that I did not run in vain or labor in vain” (Phil 2:16).

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Vanity of your mind!

Ephesians 4:18 (NIV)

¹⁸ They are darkened in their understanding and separated from the life of God because of the ignorance that is in them due to the hardening of their hearts. 

Your heart becomes hardened, cold, insensitive, unfeeling and mainly unyielding toward God in your existence! While your heart automatically becomes conditioned to the physical world of flesh-oriented type of things...   By sight, sound, feeling, taste and smell!   

How you use or process the information in your brain demonstrates wither you are going to either make good use or a total waste of your talents...

Your imagination is one of the most powerful forces you have at your disposal.  As a matter of fact, you can not consistently function contrary to the image you have inside! 

 " For as he thinks in his heart, so he is! "  Proverbs 23:7