Let the Bible speak for itself.
John defines sin as transgression of the law of God.
1 John 3:4 Whosoever committeth sin transgresseth also the law: for sin is the transgression of the law.
Paul defines the law as the Ten.
Romans 7:7 What shall we say then? Is the law sin? God forbid. Nay, I had not known sin, but by the law: for I had not known lust, except the law had said, Thou shalt not covet.
The Sabbath is the fourth commandment in the Ten.
Jesus concerning tradition vs the Ten.
Matthew 15:13,16 But he answered and said unto them, Why do ye also transgress the commandment of God by your tradition? For God commanded, saying, Honour thy father and mother: and, He that curseth father or mother, let him die the death. But ye say, Whosoever shall say to his father or his mother, It is a gift, by whatsoever thou mightest be profited by me; And honour not his father or his mother, he shall be free. Thus have ye made the commandment of God of none effect by your tradition.
What was it that Isaiah said?
Isaiah 8:20 To the law and to the testimony: if they speak not according to this word, it is because there is no light in them.
What was it that Jesus said?
Matthew 19:17 And he said unto him, Why callest thou me good? there is none good but one, that is, God: but if thou wilt enter into life, keep the commandments.