Question: Does the term "the Lord's day" in Revelation 1:10 mean Sunday or the Sabbath day—or something else?
As was mentioned in Part 1 of this series, Rev. 1:10 is the only occurrence of the phrase “the Lord’s Day” in Scripture. It does appear, however, in early Christian writings after the close of the New Testament, and always in reference to Sunday, the first day of the week, as a celebration of the resurrection. The appearance of the phrase in Revelation, which was composed around 96 AD, shows that the phrase was coming into use among Christians at the close of the apostolic period, yet was common enough even then that John did not have to explain its meaning.
As people who live under the New Covenant, Christians are free from the obligations of the Law, which was imposed upon the Jewish people, including the observance of the Sabbath:
Col. 2:16 Therefore do not let anyone judge you by what you eat or drink, or with regard to a religious festival, a New Moon celebration or a Sabbath day.
In fact, when Jewish Christians in the early church insisted that male Gentile believers be circumcised, or else they could not be saved, the apostles in Jerusalem responded that new believers should not be encumbered with any of the Old Covenant regulations:
Acts 15:28-29 It seemed good to the Holy Spirit and to us not to burden you with anything beyond the following requirements: You are to abstain from food sacrificed to idols, from blood, from the meat of strangled animals and from sexual immorality. You will do well to avoid these things.
Even the “requirements” they did stipulate were not matters of a new Law or conditions of salvation.
For a more complete look at the teaching of the New Testament on this, I encourage the reader to go to Biblegems #68, “Old Testament Sacrifices Under The New Covenant.”
“The Lord’s day” in Rev. 1:10 is translated from te keriake hemera, where “keriake,” a possessive adjective, means “belonging to the Lord.” Similar phrasing in the New Testament is used of “the Lord’s supper” (1 Cor. 11:20), where “the Lord’s” clearly refers to Jesus.
While it is true there are numerous times when the phrase “my Sabbaths” is used by God to describe the Sabbath day (Ezek. 23:38; Is. 56:4; etc.), that does not mean that the Sabbath day and the Lord’s Day are one and the same. It was the first day of the week (Sunday) on which Jesus rose from the dead (Lk. 24:13-49; Jn. 20:1-25), and the following Sunday when He appeared to His disciples (Jn. 20:26). This is why the early church set aside the first day of the week for worship, the Lord’s Supper, the preaching of the Word and giving to the needy (Acts 20:7; 1 Cor. 16:1-2).
The Sabbath celebrates the original creation; the Lord’s Day celebrates the resurrection and the new creation in Christ. The Sabbath is God’s holy day set apart for the Jewish people under the Law of Moses; the Lord’s Day affirms that:
Rom. 3:21 …a righteousness from God, apart from law, has been made known, to which the Law and the Prophets testify.