The Letter of Barnabas (74 A.D.)
“Moreover God says to the Jews, ‘Your new moons and Sabbaths cannot endure.’ You see how he says, ‘The present Sabbaths are not acceptable to me, but the Sabbath which I have made in which, when I have rested from all things, I will make the beginning of the eighth day which is the beginning of another world.’ Wherefore we Christians keep the eighth day [Sunday] with joyfulness, the day also on which Jesus rose again from the dead” (Barnabas 15:6-8).
“Therefore let no one pass judgment on you in questions of food and drink or with regard to a festival or a new moon or a sabbath.” (Colossians 2:16).
Here are some other writings that describe the Lord’s Day being celebrated on Sunday in later centuries (just for fun):
Ignatius of Antioch (110 A.D.) wrote:
“[T]hose who were brought up in the ancient order of things [i.e. Jews] have come to the possession of a new hope, no longer observing the sabbath, but living in the observance of the Lord’s day, on which also our life has sprung up again by him and by his death” (Letter to the Magnesians 8).
Justin Martyr (155 A.D.) wrote:
“[W]e too would observe the fleshly circumcision, and the sabbaths, and in short all the feasts, if we did not know for what reason they were enjoined [on] you—namely, on account of your transgressions and the hardness of your heart. . . How is it, Trypho, that we would not observe those rites which do not harm us—I speak of fleshly circumcision and sabbaths and feasts? . . . God enjoined you to keep the sabbath, and imposed on you other precepts for a sign, as I have already said, on account of your unrighteousness and that of your fathers” (Dialogue with Trypho the Jew 18, 21).
Tertullian (203 A.D.) wrote:
“Let him who contends that the Sabbath is still to be observed as a balm of salvation, and circumcision on the eighth day . . . teach us that, for the time past, righteous men kept the Sabbath or practiced circumcision, and were thus rendered ‘friends of God.’ For if circumcision purges a man, since God made Adam uncircumcised, why did he not circumcise him, even after his sinning, if circumcision purges? . . . Therefore, since God originated Adam uncircumcised and unobservant of the Sabbath, consequently his offspring also, Abel, offering him sacrifices, uncircumcised and unobservant of the Sabbath, was by him [God] commended [Gen. 4:1-7, Heb. 9:4]. . . . Noah also, uncircumcised—yes, and unobservant of the Sabbath—God freed from the deluge. For Enoch too, most righteous man, uncircumcised and unobservant of the Sabbath, he translated from this world, who did not first taste death in order that, being a candidate for eternal life, he might show us that we also may, without the burden of the law of Moses, please God” (An Answer to the Jews 2).
The Didascalia (225 A.D.) stated:
“The apostles further appointed: On the first day of the week let there be service, and the reading of the Holy Scriptures, and the oblation, because on the first day of the week our Lord rose from the place of the dead, and on the first day of the week he arose upon the world, and on the first day of the week he ascended up to heaven, and on the first day of the week he will appear at last with the angels of heaven” (Didascalia 2).
Origen (229 A.D.) wrote:
“Hence it is not possible that the [day of] rest after the Sabbath should have come into existence from the seventh [day] of our God. On the contrary, it is our Savior who, after the pattern of his own rest, caused us to be made in the likeness of his death, and hence also of his resurrection” (Commentary on John 2:28).
Victorinus (300 A.D.) wrote:
“The sixth day [Friday] is called parasceve, that is to say, the preparation of the kingdom. . . . On this day also, on account of the passion of the Lord Jesus Christ, we make either a station to God or a fast. On the seventh day he rested from all his works, and blessed it, and sanctified it. On the former day we are accustomed to fast rigorously, that on the Lord’s day we may go forth to our bread with giving of thanks. And let the parasceve become a rigorous fast, lest we should appear to observe any sabbath with the Jews . . . which sabbath he [Christ] in his body abolished” (The Creation of the World).