Sabbath as means of rooting out idolatry
"If the Sabbath is restored there will be a refusal to bow down to[idols of selfish pleasure and possessions] and we shall be awake to the danger of these idols. By having to separate out in our lives what is appropriate for Sabbath activity, we will recognize what a stronghold the pleasures and ways of the world have taken upon our minds and imaginations. Thus, Sabbath-keeping is God's revealer of idolatrous practices among His people.
"[Calls to put aside the law to magnify grace] generally mean that Christians are guided by circumstance and desire rather than by principle and conviction. Scripture ceases to rule.... There is no question that salvation is through faith in the Lord Jesus Christ, apart from obedience to the Law.... [but] How foolish it is to think of the Law as irrelevant to the believer, when the whole purpose of the gospel he loves is to put him in a frame of heart that is able to live life as God has outlined it in His holy Commandments." pg 91-92