Romans 14:4 Who art thou that judgest another man's servant? to his own master he standeth or falleth. Yea, he shall be holden up: for God is able to make him stand.
Romans 14:5 One man esteemeth one day above another: another esteemeth every day alike. Let every man be fully persuaded in his own mind.
Romans 14:6 He that regardeth the day, regardeth it unto the Lord; and he that regardeth not the day, to the Lord he doth not regard it. He that eateth, eateth to the Lord, for he giveth God thanks; and he that eateth not, to the Lord he eateth not, and giveth God thanks.
Romans 14:5 One man esteemeth one day above another: another esteemeth every day alike. Let every man be fully persuaded in his own mind.
Romans 14:6 He that regardeth the day, regardeth it unto the Lord; and he that regardeth not the day, to the Lord he doth not regard it. He that eateth, eateth to the Lord, for he giveth God thanks; and he that eateth not, to the Lord he eateth not, and giveth God thanks.
But lets address the fallacies of using these texts against the Sabbath.
First point the text does not say Sabbath anywhere, it is pure assumption that the Sabbath is included here. Now some will say but the Sabbath is a day so it has to be included. This is just a lie full stop. The primes for these verse is disputable matters as it is written:
Rom 14:1 Him that is weak in the faith receive ye, but not to doubtful disputations.
what is a doubtful disputation? It is judging someone on a topic that Scripture does not make clear. In other words makng a big deal over something that God does not make clear.
So ask yourself this, Is the bible clear that the 7th day was made Holy and set apart for Holy use and blessed by God? The answer is clearly yes no one can dispute this fact and thus it does not fall in the criteria of the topic being spoken of by Paul.
Is the bible clear that God included a reminder of this fact within the law that shows what sin is by that which is good? Yes the fourth commandment clearly shows this. So this again is not a disputable matter it is easily settled by the word of God.
See OP for the texts.
Some twist this text by saying that day includes the Sabbath and then reverse engineer the text to say that if the Sabbath is included, (They can not show that it is) Then the Sabbath then is a doubtful disputation.
As you can see this is unsound thinking, This is an attempt to justify a position that is most clearly against the clearly revealed will of God.
There is nothing doubtful about the Sabbath, This argument falls apart when we give some thought to the subject and examine the word of God.