The Sabbath is part of the Law that is fulfilled by each every believer. This they do because of the Love that they have for GOD and their fellow man.
Please reread This.
Fulfilling does not mean replacing my friend.
In regards to defining the word translated fulfilling. Here is an excerpt from Thayer's unabridged Lexicon.
1. to make full, to fill, to fill up:
2. to render full
That is how the word in question is understood. If we would look the word up in our Strong's we would see it defined thusly...
G4137 πληρόω pleroo (play-roh'-o) v.
1. to fully, completely fill
2. (literally) to cram (a net), level up (a hollow)....
To further emphasize this point here are but a few of the many other places the word is used.
Being
filled with the fruits of righteousness, which are by Jesus Christ, unto the glory and praise of God.
(Php 1:11 KJV)
For this cause we also, since the day we heard it, do not cease to pray for you, and to desire that ye might be
filled with the knowledge of his will in all wisdom and spiritual understanding;
(Col 1:9 KJV)
He that descended is the same also that ascended up far above all heavens, that he might fill all things.)
(Eph 4:10 KJV)These things have I spoken unto you, that my joy might remain in you, and that your joy might be full.
(Joh 15:11 KJV)
Wherefore also we pray always for you, that our God would count you worthy of this calling, and fulfil all the good pleasure of his goodness, and the work of faith with power:
(2Th 1:11 KJV)
Let's take a closer look shall we.
Owe no man any thing, but to love one another: for he that loveth another hath fulfilled (filled, done, crammed; completed to the uttermost) the law. For (because) this, Thou shalt no,commit adultery,Thou shalt not kill, Thou shalt not steal, Thou shalt not bear false witness, Thou shalt not covet; and if any other commandment (injunction, i.e. an authoritative prescription), it is briefly comprehended in this saying, namely, Thou shalt love thy neighbour as thyself. Love worketh no ill to his neighbour: therefore love is the fulfilling (cramming to the uttermost) of the law. And that, knowing the time, that now it is high time to awake out of sleep: for now is our salvation nearer than when we believed. The night is far spent, the day is at hand: let us therefore cast off the works of darkness, and let us put on the armour of light.
Let us walk honestly, as in the day; not in rioting and drunkenness, not in chambering and wantonness, not in strife and envying. But put ye on the Lord Jesus Christ, and make not provision for the flesh, to fulfil the lusts thereof.
(Rom 13:8-14 KJV)
Fulfilling is cramming; completing to the uttermost not replacing.
For he that loveth another hath fulfilled (filled, done, crammed; completed to the uttermost) the law.
The Law in verse eight is used in reference to the Ten Commandments. That is why Paul goes on to quote a few of them in verse nine. And thenprecedes on to broader the spectrum by mention any other commandment. That is an injunction given. In other words an authoritative prescription. Hence a commandment. Any commandment in relation to love.
As you know Romans is a letter. So All this is in context to things written in it which were previously establish.
Case and point.
GOD has said, "Say not in thine heart, Who shall ascend into heaven? (That is, to bring Christ, the Word, all that GOD would have us be. HIS Commandments; HIS Statutes) down from above Or, Who shall descend into the deep? (That is, to bring up Christ, the Word, all that GOD would have us be. HIS Commandments; HIS Statutes again from the dead.) But what saith it? The word (Christ; the Word, the commandments; HIS Statutes manifested in the flesh, our flesh through His flesh) is nigh thee, even in thy mouth, in thy heart, and in thy hand: that we may do it; that is, THE WORD OF FAITH, which we preach. And that is the Gospel, the Kingdom of GOD (CHRIST) in you. For GOD hath said, "This is the covenant that I will make with them after those days, saith the Lord, I will put my laws into their hearts, and in their minds will I write them." And HE shall be our GOD and we shall be HIS people, for it is GOD that works in us both to will and do HIS good pleasure. Christ (the Word, His Commandments, GOD's will) in us the hope of Glory. For without this faith (the Word; HIS Christ; His Commandments; HIS Statutes in our hearts and in our minds) it is impossible to please GOD. This the righteousness of GOD being manifested. The righteousness which is by the Faith of Jesus Christ; into all and upon all them that believe for there is no difference.
The verses in Romans 10:6-8; Deut. 30:11-14 ; Hebrews 8:10,11; Jeremiah 31:33 are all speaking of GOD's gift of enabling us through HIS Spirit to be as HE would have us be. We Fulfill to the uttermost HIS Commandments; HIS Statutes; HIS Word because Christ is now in our hearts and we are one as they are one. Not because of something we do. For it is HE that works in us both to will and do HIS good pleasure. Please notice that this gift in which is being spoken to the Gentiles in Romans 10 was also spoken to Israel. This Good News; the Gospel was available to us from the beginning of Moses ministry. As Hebrews 4:2 states "For unto us was the gospel preached, as well as unto them: but the word preached did not profit them, not being mixed with faith in them that heard it."
(Heb 4:2 KJV)
But it did not profit many of them because they did not utilize the Faith. Christ; the Word; HIS Commandments. HIS Statutes in their hearts, minds and in their mouths so they could to do it.
So once again we share; let's walk in Faith; the FAITH. And we shall, not fulfill the lust of the flesh, but fulfill the Love of GOD. His Commandment; HIS Statutes; HIS Word. Christ in us the EXPECTATION of GLORY; GOD!
The Sabbath is of the Commandments; HIS Statutes; HIS Word; Christ which has been place in our hearts that we do that which has placed there. This is the Gospel. The LORD thy GOD will circumcise thy hearts and the hearts of thy seed. Deut. 30:6