God has declared that He will create everything “New.” “Therefore, if anyone is in Christ, he is a new creation, the old has gone, the new has come” (2 Corinthians 5:17 NIV). But it often takes years for young Christians to realize that they need to welcome the new and give up the old with regard to their minds.
This problem reveals itself in repeated patterns of talk where joking of an ungodly kind surfaces now and then. That is a clear indicator that the person has not renewed his mind: “For out of the overflow of the heart the mouth speaks” (Matthew 12:34b NIV). So when such a problem reveals a deeper need of the mind, you should try to renew your mind.
It is like painting a rusted window. You need to scrape the surface and remove the rust and wipe away the dust. The next step involves applying primer and painting. But what if you just stop after scraping away the rust? After some days it will rust more. Likewise if you just try to remove old thinking patterns be sure that it will surface soon making more inroads into your mind.
Instead you need to put in more godly thoughts by reading the Bible and meditating on it. You need to start thinking on whatever is true, noble, right, pure, lovely and admirable. You need to think on excellent and praiseworthy things (Ref. Philippians 4:8). That will help you to renew your mind. That will help you not to conform to the thinking patterns of this world. That will help you to know God’s will (Ref. Romans 12:2) So renew your mind and be changed to the newness of God.