When a Christian argues that the Fourth Commandment no longer binds believers because Christ is our rest and has "fulfilled" the Sabbath, he is employing a principle that, if consistently applied, would dissolve the entire moral law. (I didn't invent the argument but it's sound.)
Follow the logic to its conclusion:
Christ is our God; therefore the First Commandment no longer binds us.
Christ is the image of the invisible God and the perfect revelation of the Father; therefore the Second Commandment no longer binds us.
Christ is the eternal Word and the Name above every name; therefore the Third Commandment no longer binds us.
Christ is our Sabbath rest; therefore the Fourth Commandment no longer binds us.
Christ is the everlasting Father of His people; therefore the Fifth Commandment no longer binds us.
Christ died that we might live; therefore the Sixth Commandment no longer binds us.
Christ is the faithful Husband of His bride; therefore the Seventh Commandment no longer binds us.
Christ became poor that we through His poverty might become rich; therefore the Eighth Commandment no longer binds us.
Christ is the faithful and true Witness; therefore the Ninth Commandment no longer binds us.
Christ is our all-sufficient portion and everlasting inheritance; therefore the Tenth Commandment no longer binds us.
The argument proves too much. Christ's fulfillment of the moral law does not abolish our obligation to obey it. Rather, He fulfilled it perfectly on our behalf, bore its curse in our place, and now writes that same law upon the hearts of His redeemed by the Holy Spirit.
"We take the stars from heaven, the red from our mother country, separating it by white stripes, thus showing that we have separated from her, and the white stripes shall go down to posterity, representing our liberty." —George Washington
When it comes to clear and honest thinking, there are three PCA pastors I particularly respect and regularly listen to: @matt_everhard, @GeorgeSayour, and @james_d_baird.
I could list more, of course, but these brothers have been so helpful and consistent.
@PastorSteveW@Smith_Jeffrey WLC Q. 191. What do we pray for in the second petition?
A. In the second petition (which is, Thy kingdom come) ... we pray, that the kingdom of sin and Satan may be destroyed, the gospel propagated throughout the world, the Jews called, the fullness of the Gentiles brought in ...
@PastorSteveW@Smith_Jeffrey If you read most classically Reformed authors, especially the Puritans, they explicitly believed in the future conversion of the Jews. Many prayed for the mass conversion of the Jews, which they believed to be one of the last fulfillments of prophecy before the Second Coming.