1 John 3:3-18, What is Sin?

⁴ Whosoever committeth sin transgresseth also the law: for sin is the transgression of the law. ⁵ And ye know that he was manifested to take away our sins; and in him is no sin. ⁶ Whosoever abideth in him sinneth not: whosoever sinneth hath not seen him, neither known him. ⁷ Little children, let no man deceive you: he that doeth righteousness is righteous, even as he is righteous. ⁸ He that committeth 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. ⁹ Whosoever is born of God doth not commit sin; for his seed remaineth in him: and he cannot sin, because he is born of God. ¹⁰ In this the children of God are manifest, and the children of the devil: whosoever doeth not righteousness is not of God, neither he that loveth not his brother.

1 John 3:4-8