Mature Christian is:
MEAK, HUMBLE & GENTLE LIKE JESUS
Fight sin in you, sin brings darkness, darkness belongs to your fierce enemy, the devil who roams like a lion to devour. When you sin, you invite him and his demons to destroy you in many ways. Fight sin with all your might and with the help of the Lord Jesus Christ your Savior, you were bought for a price, you do not belong to yourself anymore, you belong to Him, who died for you. Serve Him, love Him, be like Him.
Fight greed, lust, anger, wrath, slander, gossip, evil thoughts, evil desires of your heart, jealousy, love of money, envy, love of the world, love of possession, arrogance, pride, fear, worry, unbelief and many more, read the Book of Proverbs daily. God is there to help us.