Theological inquiry concerning the Sabbath: “Sabbath is necessary because it is also the part of ten commandments. It is equal to other 9 commandments. Law doesn’t give us salvation but it is necessary to be followed.”
If you are a practicing Jew, the Sabbath Day is relevant as you have placed yourself under the Law; therefore, you must keep the Law perfectly, including the Sabbath’s mandates; that is, if you seek to find righteousness (a right standing) with God the Father; unfortunately, even if you could keep the Law perfectly from a designated point forward in your life, you have already violated the Law and are condemned because there is no atonement for sin in the Law as the blood of animals is not sufficient to forgive sin (Hebrews 10:4); therefore, even if you were able to keep the Law perfectly, your sin remains and death in sin and Hell is inevitable (John 8:24).
Jesus Christ-Yeshua is our Sabbath’s rest for everyone who trusts in Him as God, Intercessor, Messiah. Jesus’ life and Crucifixion fulfilled the Law perfectly and made atonement for sin; therefore, the one who trusts in Messiah as God is not under Law but under Grace (Romans 6:14). The Christian is therefore free to worship any day, eat anything, wear any form of mixed-fabrics with the only concern being that we’re not to cause our Christian brethren to stumble by our freedom in faith in Jesus (Romans 14).
When you require others to keep a Law that does not pertain to them, you become legalistic and you are opposed to the things of God who suffered and died to set us free from the death of the letter of the Law (2 Corinthians 3:6).