Like circumcision, the passover, and all other aspects of legal, ceremonial worship during the Old Testament era, THE LEGAL SABBATH DAY WAS ESTABLISHED BY OUR GOD TO BE A SIGN, PICTURE, AND TYPE OF GRACE AND SALVATION IN CHRIST. This is not a matter of speculation and guesswork. This is exactly what God says about the matter in Exodus 31-13.

Rom 4-22 And therefore it was imputed to him for righteousness.-Rom 4-23 Now it was not written for his sake alone, that it was imputed to him--Rom 4-24 But for us also, to whom it shall be imputed, if we believe on him that raised up Jesus our Lord from the dead--Rom 4-25 Who was delivered for our offences, and was raised again for our justification.

-Save me, O God, by thy name, and judge me by thy strength.--Hear my prayer, O God- give ear to the words of my mouth.--For strangers are risen up against me, and oppressors seek after my soul- they have not set God before them. Selah.--Behold, God is mine helper- the Lord is with them that uphold my soul.--He shall reward evil unto mine enemies- cut them off in thy truth.--I will freely sacrifice unto thee- I will praise thy name, O Lord- for it is good.--For he hath delivered me out of all trouble- and mine eye hath seen his desire upon mine enemies.---Psalm 54