“That you put off, concerning your former conduct, the old man which grows corrupt according to the deceitful lusts” (Ephesians 4:22 NKJV). So how is our thinking related to whether we are a believer in Jesus or not? Paul says we were dead in our trespasses and we were what he called an old man—or woman. Not that we are old in age, but we do not have a born again heart. We have old thinking. We have old worldly beliefs. But when we are born again we are made a new man. “9 Lie not one to another, seeing that ye have put off the old man with his deeds; 10 And have put on the new man, which is renewed in knowledge after the image of him that created him” (Colossians 3:8-10). God changed us from within. We have a new heart from which we can now believe correctly and from which guides our thinking.