1John 3:1-16, John shows us the seriousness of sin; and how to overcome it:He starts with, telling us about the love of God. 3:1,reads, Behold, What manner of loved the Father hath bestowed upon us, that we should be called the sons of God:] When an unbeliever sin, they sin against there creator. But when a believer sin we sin against our loving Father. So he said if you sin ask God for, forgiveness; Confess and repent. John also gently said, Beloved, now are we the Sons of God, we do not know what we are going to be,but we know that when He appear, we shall be like Him; for we shall see Him as He is.] God is Love, and Christ came, because of that Love;] He was manifested to take away our sin; so we need to abide in Him: 3:8; He that commit sin is of the devil; for the devil sinneth from the beginning. For this purpose the Son of God was manifested, that He might destroy the works of the devil. Whosoever is born of God does not commit sin; for His seed remaineth in Him: and he cannot sin, because he is born of God. This means that no one who is true Christian, can go on sinning.
Cain was called the wicked one, 3:12-15 because he murderer his brother. Marvel not, my brethren, if the World hate you. John is saying don’t be surprise if the World hate you; the most important thing is, that you are passed from death to life because we loved the brethren.He that loveth not his brother abideth in death. whosoever hateth his brother, is a murderer and ye know that no murderer hath eternal life abiding in him. Because the lord Jesus Christ lay down His life for us: we also should lay down our life for the brethren,] Every Christian must acknowledge Christ] 3:23, read, And this is the Commandment, that we should believe on the name of His Son [God Son] Jesus Christ,John the writer said, our action should prove that unity in the Church works. when we put it into practice. He also warns us that there are counterfeit Christians. be watchful. But Love concur all.