And everyone who has this hope fixed on Him purifies himself, just as He is pure.
Everyone who practices sin also practices lawlessness; and sin is lawlessness. -1 John 3:3,4
That means we are sinning when we do not keep the sabbath
What shall we say then? Are we to continue in sin so that grace may increase? May it never be! How shall we who died to sin still live in it? -Romans 6:1,2
that means we are not allowed to sin because we are under grace
“Whoever then annuls one of the least of these commandments, and teaches others to do the same, shall be called least in the kingdom of heaven; but whoever keeps and teaches them, he shall be called great in the kingdom of heaven. -Matthew 5:19
That means, according to Yeshua, if we want to be great in His kingdom we will keep and teach the sabbath.
Seems simple enough...