I thought I could help you use your intellect, by following through what I wrote, so you could answer your own question. God is your God, not just a God for a small group of people, and God explains you are included. You say God is only for Israel, but that isn't true, God is for you, too. Christ came for all people. When we accept a new nature it does not make us perfect saints, incapable of any sin ever again. Our new nature includes that we are given choice while we live on this earth. With our new nature, we are still asked to obey God.
You can obey law, as many do who do not believe in God, obedience needs to include love and understanding of God.
The word Sabbath can come our of the mouth of people who love the Lord. In fact, it is likely to. Why are you judging me as a wrong person because I say this word? Judging people is not Christian.