Luke 4:16
"And he came to Nazareth, Where he had been brought up: and, as his custom was, he went into the synagogue on the Sabbath day, and stood up for to read."

(It was the custom of Jesus to teach in the synagogue on the Sabbath day.)

Mark 2:27-28
"And he said unto them. The sabbath was made for man, and not man for the sabbath. Therefore the Son of man is Lord also of the sabbath."

(The Son of man is Lord of the Sabbath? Then Sunday cannot be the Lord's day, because it says in the scripture above that if there is a Lord's day the Sabbath is it. Jesus never said that the Sabbath was done away, instead He claimed authority over the Sabbath.)

Ex 31:13
"Speak thou also unto the children of Israel, saying, verily my sabbaths ye shall keep: for it is a sign between me and you throughout your generations; that ye may know that I am the Lord that doth sanctify you."

(The Sabbath is the sign of God's people, that we belong to Him.
Sanctifies His people, identifies Him as Jehovah, and sets us apart.)

Ex 31:17
"It is a sign between me and the children of Israel forever for in six days the Lord made heaven and earth and on the seventh day he rested and was refreshed."

(The Sabbath is a sign forever, so it is not going to end. The Sabbath is not for the Jewish people only, it is for all of mankind. So, then the fourth commandment is still in effect for all of God's people.)

Num 15:15-16
"One ordinance shall be both for you of the congregation, and also for the stranger that sojourneth with you, an ordinance forever in your generations: as ye are, so shall the stranger be before the Lord.
One law and one manner shall be for you, and for the stranger that sojourneth with you." Num 15:15-16

(Some say the Sabbath was just for the Jewish people, but even in ancient Israel there was not one set of commands for the Israelites and another for the Gentiles. No, there was one manner for both. And it is the same way today. No double standard.)

(After the Resurrection the Sabbath was still being observed)

Acts 13:42
"And when the Jews were gone out of the synagague the Gentiles besought that these words might be preached to them the next sabbath."

(The disciples still kept the sabbath and holy days after the resurrection and taught Gentiles to do the same. Paul taught the Gentiles and made them wait till next sabbath for more preaching. Why didn't Paul usher in Sunday at this time? If it was done away? Surely he would have known if there was to be a new way, wouldn't he?)

Rom 10:12
"For the is no difference between the Jew and the Greek: for the same Lord over all is rich unto all that call upon Him."

Acts 17:1-2
"Now when they had passed through Amphipolis and Appollonica, they came to Thessalonica, where was a synagogue of the Jews. And Paul, as his manner was, went in unto them, and three sabbath days reasoned with them out of the scriptures."

ICor 16:1-2
"Now concerning the collection for the saints, as I have given order to the churches of Galatia, even so do ye. Upon the first day of the week let every one of you lay by him in store, as God hath prospered him, that there be no gathering when I come."

(This scripture says nothing about a church service. Instead they went out into the fields to gather. This was real work. Considerably harder than going to the field today on a Sunday morning to gather would be, because we now have modern equipment to do the work for us. Also, they couldn't work on the Sabbath so they did the gathering on the first day of the week.)

Col 2:16-17
"Lo, let no man therefore jude you in meat or in drink or in respect of an holy day, or of the new moon, or of the sabbath days.
Which are a shadow of things to come; but the body is of Christ."

(These people in Colosse were Gentiles. The people who lived in Colosse were observing the pagan holidays and were sun worshippers. So obviously, if the newly converted Christians in that area were receiving criticism, it would have to have been because they were observing God's holy days and Sabbaths. Would not have even been an issue if they had been doing as the Gentiles around them, and worshipping on the day of the sun.)

Acts 20:6-7
"And we sailed away from Philippi after the days of unleavened bread, and came unto Troas in five days; where we abode seven days. And upon the first day of the week, when the disciples came together to break bread. Paul preached unto them, ready to depart on the morrow; and continued his speech until midnight."

(This took place on a Saturday night. This was simply a meal too, not the Lord's supper. On Sunday Paul journeyed which in those days was not a restful thing to do. Usually meant walking many miles.)

(The Sabbath was kept by the church until AD 325. When the Sabbath day was changed at the Council of Nicaea by the Roman emperor Constantine.
Christians at this time were martyred for keeping Holy days and the Sabbath.)

Sunday-Funk and Wagnall Encyclopedia
"first day of the week. Its English name, and German name (Sonntag) as well, is derived from Latin (dies solis), "Sun's day," the name of a pagan Roman holiday.
In the early days of Christianity Sunday bagan to replace the Sabbath and to be observed to honor the resurrection of Christ. Sunday was instituted as a day of rest, consecrated especially to the service of God, by the Roman emperor Constantine 1. Since the 4th century ecclesiastical and civil legislation has regulated work on Sunday and service attendance."