Sin is the transgression of the law. 1 John 3:4. RC 49.1
The desire for an easy religion that requires no striving, no self-denial, no divorce from the follies of the world, has made the doctrine of faith, and faith only, a popular doctrine; but what saith the Word of God? Says the apostle James: “What doth it profit, my brethren, though a man say he hath faith, and have not works? can faith save him? ... Wilt thou know, O vain man, that faith without works is dead? Was not Abraham our father justified by works, when he had offered Isaac his son upon the altar? Seest thou how faith wrought with his works, and by works was faith made perfect? ... Ye see then how that by works a man is justified, and not by faith only” (James 2:14-24). RC 49.2
The testimony of the Word of God is against this ensnaring doctrine of faith without works. It is not faith that claims the favor of Heaven without complying with the conditions upon which mercy is to be granted, it is presumption; for genuine faith has its foundation in the promises and provisions of the Scriptures.... RC 49.3
The commission of a known sin silences the witnessing voice of the Spirit and separates the soul from God. “Sin is the transgression of the law.” And “whosoever sinneth [transgresseth the law] hath not seen him, neither known him” (1 John 3:6). Though John in his Epistles dwells so fully upon love, yet he does not hesitate to reveal the true character of that class who claim to be sanctified while living in transgression of the law of God. “He that saith, I know him, and keepeth not his commandments, is a liar, and the truth is not in him. But whoso keepeth his word, in him verily is the love of God perfected” (chap. 2:4, 5). RC 49.4
Here is the test of every man's profession. We cannot accord holiness to any man without bringing him to the measurement of God's only standard of holiness in heaven and in earth. If men feel no weight of the moral law, if they belittle and make light of God's precepts, if they break one of the least of these commandments, and teach men so, they shall be of no esteem in the sight of Heaven, and we may know that their claims are without foundation. RC 49.5
And the claim to be without sin is, in itself, evidence that he who makes this claim is far from holy. It is because he has no true conception of the infinite purity and holiness of God or of what they must become who shall be in harmony with His character; because he has no true conception of the purity and exalted loveliness of Jesus, and the malignity and evil of sin, that man can regard himself as holy.—The Great Controversy, 472, 473. RC 49.6
It was the righteousness revealed in His [Christ's] life that distinguished Him from the world.—The Upward Look, 303. RC 49.7