He says in Exodus: 20: 8 Remember the Sabbath day, to keep it holy. 9 Six days shalt thou
labour, and do all thy work:
10 But the seventh day is the sabbath of the LORD thy God: in it thou shalt not do any work,
thou, nor thy son, nor thy daughter, thy manservant, nor thy maidservant, nor thy cattle, nor
thy stranger that is within thy gates: 11 For in six days the LORD made heaven and earth,
the sea, and all that in them is, and rested the seventh day: wherefore the LORD blessed the
Sabbath day, and hallowed it.

God specifically names the seventh day of the week,  if He had meant any day of the week,
would He have specified the seventh day?  He further states that it is the seventh day that He
has blessed, not any other day.

14 Ye shall keep the sabbath therefore; for it is holy unto you: every one that defileth it shall
surely be put to death: for whosoever doeth any work therein, that soul shall be cut off from
among his people.
15 Six days may work be done; but in the seventh is the sabbath of rest, holy to the LORD:
whosoever doeth any work in the sabbath day, he shall surely be put to death.
16 Wherefore the children of Israel shall keep the sabbath, to observe the sabbath
throughout their generations, for a perpetual covenant.
17 It is a sign between me and the children of Israel for ever: for in six days the LORD made
heaven and earth, and on the seventh day He rested, and was refreshed.

* It is a sign between Yahweh, the true God, and His people.  Anyone who observes the
seventh day is declaring that the Creator who made the earth and all in it in six days and
rested on the seventh, is his God.

Jesus (Yahshua) kept the seventh day.  The Catholic Church in 1893 proved by the scriptures
that He observed the seventh day and His apostles did also even through the years after His
crucifixion.  Below is an introduction to this proof.

]Why do Protestants beep ,Sunday?
.FEBRUARY 24,  The General Conference of
Seventh-day Adventists adapted certain resolutions appealing to the government and people
of the United States from the decision of the Supreme Court declaring this to be a Christian
nation, and from the action of Congress in legislating upon the subject of religion, and
remonstrating against the principle and all the consequences of the same. In March 1893, the
International Religious Liberty Association printed these resolutions in a tract entitled
Appeal and Remonstrance. On receipt of one of these, the editor of the Catholic Mirror of
Baltimore, Maryland, published a series of four editorials, which appeared in that paper
September, 2, 9, 16, and 23, 1893. The Catholic Mirror was the official organ of Cardinal
Gibbons and the Papacy in the United States. These articles, therefore, although not written
by the Cardinal's own hand, appeared under his official sanction, and as the expression of the
Papacy to Protestantism, and the demand of the Papacy that Protestants shall render to the
Papacy an account of why they keep Sunday and also of how they keep it.

The following article (excepting the notes in brackets/minor formatting and section headings
for readability, and the two Appendixes) is a reprint of these editorials, including the title on
page 2.    

                           ROME'S CHALLENGE
                       THE CHRISTIAN SABBATH


Below is what the Catholic Mirror printed about  the Sabbath in the New Testament.

Investigating the Sabbath in the New Testament

We now approach a period covering little short of nineteen centuries, and proceed to
investigate whether the supplemental divine teacher - the New Testament- contains a decree
canceling the mandate of the old law, and, at the same time, substituting a day for the
divinely instituted Sabbath of the old law, viz., Saturday; for, inasmuch as Saturday was the
day kept and ordered to be kept by God, divine authority alone, under the form of a canceling
decree, could abolish the Saturday covenant, and another divine mandate, appointing by
name another day to be kept "holy," other than Saturday, is equally necessary to satisfy the
conscience of the Christian believer. The Bible being the only teacher recognized by the
Biblical Christian, the Old Testament failing to point out a change of day, and yet another
day than Saturday being kept "holy" by the Biblical world, it is surely incumbent on the
reformed Christian to point out in the pages of the New Testament the new divine decree
repealing that of Saturday and substituting that of Sunday, kept by the Biblicals since the
dawn of the Reformation.
Examining the New Testament from cover to cover, critically, we find the Sabbath referred to
sixty-one times. We find, too, that the Saviour invariably selected the Sabbath (Saturday) to
teach in the synagogues and work miracles. The four Gospels refer to the Sabbath (Saturday)
fifty-one times.
  In one instance the Redeemer refers to Himself as "the Lord of the Sabbath," as
mentioned by Matthew and Luke, (2) but during the whole record of His life, whilst invariably
keeping and utilizing the day (Saturday), He never once hinted at a desire to change it. His
apostles and personal friends afford to us a striking instance of their scrupulous observance
of it after His death, and, whilst His body was yet in tomb, Luke (23:56) informs us: "And
they returned and prepared spices and ointments, and rested on the sabbath day according to
the commandment. " "but on the first day of the week, very early in the morning, they
came, bringing the spices they had prepared." The "spices" and "ointments" had been
prepared Good Friday evening, because "the Sabbath drew near." Verse 54. This action on
the part of the personal friends of the Saviour, proves beyond contradiction that after His
death they kept "holy" the Saturday, and regarded the Sunday as any other day of the week.
Can anything, therefore, be more conclusive than the apostles and the holy women never
knew any Sabbath but Saturday, up to the day of Christ's death?  

The article further states :

Did Jesus change the Sabbath Day?

Having proved to a demonstration that the Redeemer, in no instance, had, during the period
of His life, deviated from the faithful observance of the Sabbath (Saturday), referred to by
the four evangelists fifty-one times, although He had designated Himself "Lord of the
Sabbath," He never having once, by command or practice, hinted at a desire on His part to
change the day by the substitution of another and having called special attention to the
conduct of the apostles and the holy women, the very evening of His death, securing
beforehand spices and ointments to be used in embalming His body the morning after the
Sabbath (Saturday), as St. Luke so clearly informs us (Luke 24:1), thereby placing beyond
peradventure, the divine action and will of the Son of God during life by keeping the Sabbath
steadfastly; and having called attention to the action of His living representatives after his
death, as proved by St. Luke; having also placed before our readers the indisputable, fact that
the apostles for the following thirty years (Acts) never deviated from the practice of their
divine Master in this particular, as St. Luke (Acts 18:4) assures us: "And he [Paul] reasoned
in the synagogue every Sabbath [Saturday], and persuaded the Jews and the Greeks." The
Gentile converts were, as we see from the text, equally instructed with the Jews, to keep the
Saturday, having been converted to Christianity on that day, "the Jews and the Greeks"

Having also called attention to the texts of the Acts bearing on the exclusive use of the
Sabbath by the Jews and Christians for thirty years after the death of the Saviour as the only
day of the week observed by Christ and His apostles, which period exhausts the inspired
record, we now proceed to supplement our proofs that the Sabbath (Saturday) enjoyed this
exclusive privilege, by calling attention to every instance wherein the sacred record refers to
the first day of the week.

This article in the Catholic Mirror goes on to say that the Catholic Church is the one that
changed the Sabbath from Saturday to Sunday,

Sunday as day of worship is Catholic creation.

Before closing this series of articles, we beg to call the attention of our readers once more to
our caption, introductory of each; viz., 1. The Christian Sabbath, the genuine offspring of the
union of the Holy Spirit with the Catholic Church His spouse. 2. The claim of Protestantism
to any part therein proved to be groundless, self-contradictory, and suicidal.

The first proposition needs little proof. The Catholic Church for over one thousand years
before the existence of a Protestant, by virtue of her divine mission, changed the day from
Saturday to Sunday. We say by virtue of her divine mission, because He who called Himself
the "Lord of the Sabbath," endowed her with His own power to teach, "he that heareth you,
heareth Me;" commanded all who believe in Him to hear her, under penalty of being placed
with "heathen and publican;" and promised to be with her to the end of the world. She holds
her charter as teacher from Him - a charter as infallible as perpetual. The Protestant world at
its birth found the Christian Sabbath too strongly entrenched to run counter to its existence;
it was therefore placed under the necessity of acquiescing in the arrangement, thus implying
the Church's right to change the day, for over three hundred years. The Christian Sabbath is
therefore to this day, the acknowledged offspring of the Catholic Church as spouse of the
Holy Ghost, without a word of remonstrance from the Protestant world.

Remember this was published in a Catholic publication so therefore had the approval of both
Cardinal Gibbons and the Pope.

There should not be any question that the seventh day is the day the scriptures designate as
the Sabbath.  For those who hold that the Bible is the final authority, they must observe the
seventh day, or be classified as a practicing sinner.

We have seen that according to the scriptures, the seventh day (Saturday) is the day that
Yahweh (God) set aside and blessed as the day of rest and commanded man to keep it holy by
not doing any work on that day.  Also that according to the scriptures, the day has not been
changed from Saturday (the seventh day) to Sunday (the first day).  We have also seen that
according to the Catholic Church that it was that institution, claiming that they have God's
authority to change His laws, who claim that Sunday is the Sabbath, the day of rest.  

It is your decision to decide if the Catholic Church has been given the authority to do this, or
whether it is a false claim by men who usurp the authority of the Creator.  If you decide that
God would not put such power in the hands of men, power to change His laws to suit their own
concept of what is right in order to satisfy their own carnal desires, then you must decide
whether you will follow God or follow men.  Remember what the scriptures say about this:
Acts 4:19 But Peter and John answered and said to them, "Whether it is right in the sight of
God to give heed to you rather than to God, you be the judge;  

Remember they were speaking to the Sanhedrin, who claimed authority from God.