There is no NT scripture that identifies Saturday as the Lords day.
Sure there is and it has been provided in the very post you are quoting from. Maybe you did not read it...
WHAT DAY IS THE "LORD'S DAY" ACCORDING TO SCRIPTURE?
MATTHEW 12:8 [8],
For the Son of man is Lord even of the SABBATH DAY.
Which day is the Lord's Day? Yeps THE SABBATH DAY (
MATTHEW 12:8;
MARK 2:27-28). There is NO scripture that says Sunday or the FIRST DAY of the week is the Lords Day though.
Nine of the ten commandments are reiterated multiple times in the NT, the sabbath commandment is never mentioned.
Maybe you need a new bible. Sounds like you a missing some pages out of yours or maybe you do not own a bible pehaps its time to buy one? Everyone of God's 10 commandments are all through the new testament scriptures both individually and collectively. Let's have a look at some in relation to God's 4th that you say are never mentioned...
What did Jesus and the Apostles teach about the Sabbath in the New Testament?
1. It is lawful to do good on the Sabbath (Matthew 12:1-8; 10-12; 24:20;
Mark 3:1-5;
Luke 6:1-10; 13:14-16; 14:1-5;
John 7:22-23; 9:14;
Mark 1:21;
Mark 6:2;
Luke 4:16; 31;
Luke 14:1; 23:56)
2. Jesus made the Sabbath for all mankind (
Hebrews 1:2; John 1:1-3; 14; Ephesians 3:9; Colossians 1:16-17; Mark 2:27)
3. Jesus is Lord of the Sabbath (
Mark 2:28)
4. If you do not believe and follow God you cannot enter His Sabbath rest (
Hebrews 4)
5. It is one of God’s 10 commandments we break it we are guilty or breaking all (
James 2:8-12)
6. Breaking it is sin (
1 John 3:4)
7. God’s true followers keep it Holy as God commanded (Revelation 14:12; Revelation 22:14; Ezekiel 20:20)
8. Jesus is our example and he kept the Sabbath (Matthew 12:1-8; 10-12; 24:20;
Mark 3:1-5;
Luke 6:1-10; 13:14-16; 14:1-5;
John 7:22-23; 9:14;
Mark 1:21;
Mark 6:2;
Luke 4:16; 31;
Luke 14:1; 23:56;
John 2:6; Matthew 16:24; 1 Cor 11:1; Ephesians 5:1-21; Peter 2:20-22)
9. The Apostle kept the Sabbath (Acts 13:14; 13:27; 13:44; 15:21; 16:13; 17:2; 18:4; Rev 1:10)
10. God's people wil continue keeping the Sabbath in the new heavens and new earth *Isaiah 66:22-23
Let's finish up with this one and here the conclusion of the story... Are you ready for it???
11. Hebrews 4:9,
SO THEN IT REMAINS FOR THE PEOPLE OF GOD TO KEEP THE SABBATH
The above is not exhaustive but it does show you need a new bible or perhaps you should start reading it for yourself and stop listening to the teachings and traditions of men that break the commandments of God. According to the scriptures *HEBREWS 10:26-39 our salvation depends on it. There is not one scripture on all of God's Word that says God's 4th commandment has been abolished and we are now commanded to keep Sunday as a Holy day. This is a man made teaching and tradition that breaks the commandments of God that JESUS warns us about in Matthew 15:3-9
The writings of the early Christians make it clear that Christians abandoned the Jewish custom of worship on the Sabbath (seventh day) and instead held the first day, which they called the Lord's Day, to be the sacred day of worship. One of the simplest explanations on the subject comes from Tertullian, around 200 AD....
The OP here is asking for "SCRIPTURE" that show that "SUNDAY" or the first day of the week is "THE LORDS DAY" it is not asking for man made teachings and traditions that break the commandments of God and lead others away from the Word of God.
According to the biblical and historical records, God's people all throught time to this very present day from JESUS to the Apostles after the death and resurrection of JESUS to God's people after the death of the Apostles have always kept God's 4th commandment unbroken according to Gods 4th commandment of the 10 commandments to this very present day.
Let's look at some of the evidence, both biblically and historically...
Jesus kept and followed the Sabbath which was his custom and taught us how to truly keep the Sabbath holy according to God's 4th commandment *
Luke 4:16;
Matthew 12:1-12;
Mark 2:27-28. JESUS even warned his disciples in the future after his death and resurrection that they would still be keeping the Sabbath *
Matthew 24:20 before the destruction of Jerusalem. After the death and resurrection of JESUS the Apostles continued keeping the Sabbath according to God's LAW which was also the custom of Paul the Apostle *Acts 13:14; 13:27; 13:44; 15:21; 16:13; 17:2; 18:4
Now even after the death of JESUS and all the Apostles the disciples of JESUS have kept Gods 4th commandment unbroken to this very present day....
Sabbath Observance - The first Century A.D.
JOSEPHUS
"There is not any city of the Grecians, nor any of the Barbarians, nor any nation whatsoever, whither our custom of resting on the seventh day hath not come!" M'Clatchie, "Notes and Queries on China and Japan" (edited by Dennys), Vol 4, Nos 7, 8, p.100.
PHILO
Declares the seventh day to be a festival, not of this or of that city, but of the universe. M'Clatchie, "Notes and Queries," Vol. 4, 99
So we have incontrovertible proof that the observance of sunday was NOT practiced by the apostolic church of the first century. Although the poison of apostasy had already begun, it did not reach the ascendancy until the passage of a few more centuries.
The next installment will show the historical record of the early christians observing the true seventh day Sabbath in the second century A.D.
Sabbath Observance - The Second Century A.D.
EARLY CHRISTIANS - 2nd Century
"The primitive Christians had a great veneration for the Sabbath, and spent the day in devotion and sermons. And it is not to be doubted but they derived this practice from the Apostles themselves, as appears by several scriptures to the purpose." "Dialogues on the Lord's Day," p. 189. London: 1701, By Dr. T.H. Morer (A Church of England divine).
EARLY CHRISTIANS - 2nd Century
"...The Sabbath was a strong tie which united them with the life of the whole people, and in keeping the Sabbath holy they followed not only the example but also the command of Jesus." "Geschichte des Sonntags," pp.13, 14
EARLY CHRISTIANS - 2nd Century
"The Gentile Christians observed also the Sabbath," Gieseler's "Church History," Vol.1, ch. 2, par. 30, 93.
EARLY CHRISTIANS - 2nd Century
"The primitive Christians did keep the Sabbath of the Jews;...therefore the Christians, for a long time together, did keep their conventions upon the Sabbath, in which some portions of the law were read: and this continued till the time of the Laodicean council." "The Whole Works" of Jeremy Taylor, Vol. IX,p. 416 (R. Heber's Edition, Vol XII, p. 416).
EARLY CHRISTIANS - 2nd Century
"It is certain that the ancient Sabbath did remain and was observed (together with the celebration of the Lord's day) by the Christians of the East Church, above three hundred years after our Saviour's death." "A Learned Treatise of the Sabbath," p. 77
Note: By the "Lord's day" here the writer means Sunday and not the true Sabbath," which the Bible says is the Sabbath. This quotation shows Sunday coming into use in the early centuries soon after the death of the Apostles. It illustrates the apostasy that Paul the Apostle foretold of when he spoke about a great "falling away" from the Truth that would take place soon after his death.
"From the apostles' time until the council of Laodicea, which was about the year 364, the holy observance of the Jews' Sabbath continued, as may be proved out of many authors: yea, notwithstanding the decree of the council against it." "Sunday a Sabbath." John Ley, p.163. London: 1640.
Now I am happy to continue here just let me know as I can provide historical references all through time past the 2nd centuary AD for every century to this very present day. All you have provided is man made teachings and traditions from the Roman Catholic Church that deny God's Word.
Who should we follow; the words of men that break the commandments of God or the Word of God?