The Old Man:
“This I say, therefore, and testify in the Lord, that you should no longer walk as the rest of the Gentiles walk, in the futility of their mind, having their understanding darkened, being alienated from the life of God, because of the ignorance that is in them, because of the blindness of their heart; who, being past feeling, have given themselves over to lewdness, to work all uncleanness with greediness. Ephesians 4:17-19 (NKJV)
The above description the Word of God is giving for the man who comes into this world with ignorance in them and they are separated from God and live in darkness. If we search in darkness you cannot find anything quickly or see properly and all things look different when the light is on. Many things we do innocently looks not harmful, but will bring terrible consequences. This is how many suffer and do not understand why this is happening to them.
The New Man:
“But you have not so learned Christ, if indeed you have heard Him and have been taught by Him, as the truth is in Jesus: that you put off, concerning your former conduct, the old man which grows corrupt according to the deceitful lusts, and be renewed in the spirit of your mind, and that you put on the new man which was created according to God, in true righteousness and holiness.” Ephesians 4:20-24 (NKJV)
We should know the Lord Jesus and learn from Him who said “I am the light of the world” John 8:12(NKJV) and “I am the way, the truth and the life” John 14:6(NKJV). After learning from Him how to walk in the light, we should make drastic changes in the way we think, will and act. None of the old conducts should be there in our lives, all should have been renewed with new conducts of righteousness and holiness as God is. Come out of darkness into the light of the Son, who God loves.
“He has delivered us from the power of darkness and conveyed us into the kingdom of the Son of His love, in whom we have redemption through His blood, the forgiveness of sins. He is the image of the invisible God, the firstborn over all creation. For by Him all things were created that are in heaven and that are on earth, visible and invisible, whether thrones or dominions or principalities or powers. All things were created through Him and for Him.” Colossians 1:13-16 (NKJV)