Some Sabbatarian Christians maintain that the Catholic Church changed the day of worship from Sabbath to Sunday, starting with a Sunday law enacted by Constantine the Great (306-337 A.D.) in 321 A.D. The assumption here is that Constantine put into place a religious law. But Constantine did not enact a Christian law, but a civil one. He could not have been a Catholic, since the Catholic Church as was known during the Reformation period was not even formally organized until several centuries later. It is even doubtful that he was even a Christian, though some make that claim. Christians by this time were already meeting together for worship on the first day of the week. Many, if not most, had been doing so for at least a couple centuries before Constantine arrived on the scene. They did not call this day Sunday, but rather referred to it as the Lord's Day, in honor of Christ's resurrection from the dead.

The claim by the Catholic Church in some of their catechisms that they changed the sanctity of the Sabbath day to Sunday is not evidence that they actually did so. The New Testament does not anywhere make Sunday holy, neither does it make the Sabbath holy. The emphasis had been taken away from the day and placed on Christ, making the observance of particular days no longer necessary. The Catholic Church claims that Peter was the first Pope. It also claims that Mary, the mother of Jesus, is a co-regent with Christ in Heaven now. It is doubtful that most Sabbatarian Christians, if any at all, believe this. Why accept what the Catholic Church says regarding transferring the sanctity of the Sabbath day to Sunday, while not believing Peter to be the first Pope, or that Mary is a co-regent with Christ in Heaven? Scripture does not really portray Peter to be the first Pope, neither does it say that Mary currently is a ruler with Jesus in Heaven. She was no more a saint than any other Christian. And history does not support statements by the Catholic Church that they changed the day of worship from Sabbath to Sunday. This is an inconsistent argument that fails to make any sense.

The early Christian Church fathers of the 1st and 2nd centuries A.D. did not consider the Sabbath day to be a day all Christians were obligated to observe. They gave a different testimony. While the following epistles and statements are not in Scripture and should therefore not be considered canonical, they help to provide useful historical information regarding prevalent beliefs of the early Church in its first centuries.

Ignatius was bishop of Antioch in Syria (c. 1st-2nd century A.D.) and martyred in Rome by beasts (c. 105-116 A.D.). On his way to Rome, he visited and wrote to various churches, warning and exhorting them. He also wrote ahead to Rome to Polycarp, bishop of Smyrna. Ignatius warned the Church against heresies that threatened peace and unity, he opposed Gnosticism and Docetism, and in his Epistle to Smyrna, insisted that Christ came in the flesh not just in spirit.

The Epistle of Ignatius to the Magnesians 8-10 (c. 110 A.D.)
"Do not be deceived by strange doctrines or antiquated myths, since they are worthless. For if we continue to live accordance with Judaism, we admit that we have not received grace. For the most godly prophets lived in accordance with Christ Jesus. This is why they were persecuted, being inspired as they were by His grace in order that those who are disobedient might be fully convinced that there is one God who revealed Himself through Jesus Christ His Son, who is His Word which came forth from silence, who in every respect pleased Him who sent Him. If, then, those who had lived in antiquated practices came to newness of hope, no longer keeping the Sabbath but living in accordance with the Lord's day, on which our life also arose through Him and His death (which some deny), the mystery through which we came to believe, and because of which we patiently endure, in order that we might be found to be disciples of Jesus Christ, our only teacher, how can we possibly live without Him, whom even the prophets, who were His disciples in the Spirit, were expecting as their teacher? Because of this He for whom they rightly waited raised them from the dead when He came. Therefore let us not be unaware of His goodness. For if He were to imitate the way we act, we are lost. Therefore, having become His disciples, let us learn to live in accordance with Christianity. For whoever is called by any other name than this one does not belong to God. Throw out, therefore, the bad leaven, which has become stale and sour, and reach for the new leaven, which is Jesus Christ. Be salted with Him, so that none of you become rotten, for by your odor you will be examined. It is utterly absurd to profess Jesus Christ and to practice Judaism. For Christianity did not believe in Judaism, but Judaism in Christianity, in which "every tongue" believed and "was brought together" to God." (10)

The Epistle of Barnabas was probably not authored by the Barnabas of the New Testament. The writer repudiates the claims of Jewish Christians at the time who advocated adhering to observance of the Mosiac Law. He also argued that Christ provided salvation and man is no longer bound by the Law. This letter compares holy life to unrighteousness.

Epistle of Barnabas 2:4-6 (c. 130 A.D.)
"For He has made it clear to us through all the prophets that He needs neither sacrifices nor whole burnt offerings nor general offerings, saying on one occasion: 'What is the multitude of your sacrifices to Me?' says the Lord. 'I am full of whole burnt offerings, and I do not want the fat of lambs and blood of bulls and goats, not even if you come to appear before Me. For who demanded these things from your hands? Do not continue to trample My court. If you bring fine flour, it is in vain; incense is detestable to Me; your new moons and sabbaths I cannot stand.' Therefore He has abolished these things, in order that the new law of our Lord Jesus Christ, which is free from the yoke of compulsion, might have its offering, one not made by man."

Epistle of Barnabas 15:8-9 (c. 130 A.D.)
"Finally, He says to them: 'I cannot bear your new moons and sabbaths.' You see what He means: it is not the present sabbaths that are acceptable to Me, but the one that I have made; on that Sabbath, after I have set everything at rest, I will create the beginning of an eighth day, which is the beginning of another world. This is why we spend the eighth day in celebration, the day on which Jesus both arose from the dead and, after appearing again, ascended into heaven." (11)

The Didache or The Teaching of the Twelve Apostles was an 11th century manuscript discovered by Philotheus Bryennois. It consists of various parts, starting with the Two Ways ethical instruction and including community rules for liturgical practices and leadership conduct, before ending with a short apocalyptic section. While some of the material might go back before the year 100 A.D., the current form of the document probably dates to the mid-second century at the earliest.

The Didache (or The Teaching of the Twelve Apostles) 14:1 (c. 70 A.D.)
"On the Lord's own day gather together and break bread and give thanks, having first confessed your sins so that your sacrifice may be pure." (12)

The Ecclesiastical History of Eusebius Pamphilus (c. 260-339 A.D.) is probably one of the most important works on early Church history available, covering the events of its first three centuries. As one born during the early Church period, Eusebius was an able historian who had a close view of the events that helped shape the historical and theological developments of the early Church.

Eusebius Ecclesiastical History, Book 1, Chapter 5 (c. 315 A.D.)
"For as the name Christians is intended to indicate this very idea, that a man, by the knowledge and doctrine of Christ, is distinguished by modesty and justice, by patience and a virtuous fortitude, and by a profession of piety towards the one and only true and supreme God; all this no less studiously cultivated by them than by us. They did not, therefore, regard circumcision, nor observe the Sabbath, neither do we; neither do we abstain from certain foods, nor regard other injunctions, which Moses subsequently delivered to be observed in types and symbols, because such things as these do not belong to Christians." (13)

Eusebius Ecclesiastical History, Book 3, Chapter 27 (c. 315 A.D.)
"The Ebionites cherished low and mean opinions of Christ. For they considered Him a plain and common man, and justified only by His advances in virtue, and that He was born of the Virgin Mary, by natural generation. With them the observance of the law was altogether necessary, as if they could not be saved, only by faith in Christ and a corresponding life. These, indeed, thought on the one hand that all of the epistles of the apostles ought to be rejected, calling him an apostate from the law, but on the other, only using the gospel according to the Hebrews, they esteem the others as of little value. They also observe the Sabbath and other discipline of the Jews, just like them, but on the other hand, they also celebrate the Lords days very much like us, in commemoration of His resurrection." (14)

Eusebius Ecclesiastical History, Book 5, Chapter 23 (c. 315 A.D.)
"The churches throughout the rest of the world observe the practice that has prevailed from apostolic tradition until the present time, so that it would not be proper to terminate our fast on any other but the day of the resurrection of our Savior. Hence there were synods and convocations of the bishops on this question; and all unanimously drew up the ecclesiastical decree, which they communicated to all the churches in all places, that the mystery of our Lords resurrection should be celebrated on no other day than the Lords day." (15)

Irenaeus, Bishop of Lyons (c. 178 A.D.)
"The duty of celebrating the mystery of the resurrection of our Lord may be done only on the day of the Lord." (16)

Justin Martyr (c. 100-165 A.D.) lived during the reign of Antonius Pius and suffered martyrdom in 165 A.D. during the reign of Marcus Aurelius. He was an enthusiastic evangelist of the Gospel, and after traveling widely throughout the Roman Empire settled in Rome as a Christian teacher. While there, neighboring philosophers plotted against him because of his Christian profession, brought him up before the Roman authorities, who carried out his execution by beheading him.

The First Apology of Justin, Chapter 67
"And on the day called Sunday, all who live in cities or in the country gather together to one place, and the memoirs of the apostles or the writings of the prophets are read, as long as time permits; then, when the reader has ceased, the president verbally instructs, and exhorts to the imitation of these good things ... But Sunday is the day on which we all hold our common assembly, because it is the first day on which God, having wrought a change in the darkness and matter, made the world; and Jesus Christ our Savior on the same day rose from the dead." (17)

Some Christians would say that these epistles and statements are unreliable and reflect a general apostasy that was going on in the Church at the time. But this is the Church of which Christ said "the gates of Hades shall not overpower it." Also, the men who wrote letters such as these to the early Christians were the type of people of whom were spoken in Hebrews 11.

Many early Church leaders and followers of Christ such as Ignatius, Polycarp and Justin Martyr, to name a few, suffered severe persecution and eventual martyrdom at the hands of the Romans for spreading the Gospel of Christ. But to keep to the main point, Sabbath-keeping was not a requirement in those days for all Christians, nor was it generally observed. And this was going on long before Constantine the Great enacted his civil Sunday law.