Repentance is the activity of reviewing one's actions and feeling regret for past wrongs. it generally involves a commitment to personal change and resolving to live a more responsible life.
Biblically, repentance is confession to God ceasing from sin against God in order to gain forgiveness.
Repentance is as important as, it was the first sermon that Jesus preached after his baptism and testing in the wilderness. The bible said in Matthew 4:17; "From that time Jesus began to preach, and to say, Repent: for the kingdom of heaven is at hand".
As a christian, it doesn't matter how much you pronounce your LOVE for JESUS CHRIST, if you refuse to CHANGE YOU OLD WAYS you are not different from those whom you address to LOVE Jesus Christ. The truth is this, JESUS LOVES YOU.
Bible said in 1 Corinthians 5:17; "Therefore if any man be in Christ, he is a new creature: old things are passed away; behold, all things are become new".
The new life this scripture is talking about is putting away old deeds, being reconcilled to God though Jesus Christ. Fufilling the righteousness that comes through faith in Jesus Christ. Desiring to be like him, to suffer with him and to share in his glory.
You may say, It is not as easy as he has written, i know also but God gives the gift of his promised Holy Spirit to those who are willing, he is our helper to achieve it. Isaiah 1:19 says "If ye be willing and obedient, ye shall eat the good of the land".
Brothers and Sisters even Apostle Paul said in Philippians 3:13-14; "Brethren, I count not myself to have apprehended: but this one thing I do, forgetting those things which are behind, and reaching forth unto those things which are before, I press toward the mark for the prize of the high calling of God in Christ Jesus.