Christians should set apart every day unto to the Lord as a sacrifice of worship, but the first day of the week has been specifically distinguished from the other six days by God. This special day was prophesied in the Old Testament:
I thank you that you have answered me and have become my salvation. 22The stone that the builders rejected has become the cornerstone. 23This is the LORD’s doing; it is marvelous in our eyes. 24This is the day that the LORD has made; let us rejoice and be glad in it (Psalm 118:21—24).
Christians often use this passage to teach that we should rejoice in every day that God has made. But more correctly this passage speaks of a specific day in which would should specially rejoice. This special day that the Lord has made is the one on which “the stone that the builders rejected has become the cornerstone.” Peter explains what this special day is in Acts 4:10—11:
Let it be known to all of you and to all the people of Israel that by the name of Jesus Christ of Nazareth, whom you crucified, whom God raised from the dead—by him this man is standing before you well. 11This Jesus is the stone that was rejected by you, the builders, which has become the cornerstone.
Peter indicates that this special day prophesied in Psalm 118 is the day on which Jesus the Messiah raised from the dead, which all four Gospels tell us was the first day of the week.
This day of Christ’s victory over sin and death is one in which Christians should rejoice in a special way different from the other six days of the week. This special set-apart day is specifically designated as “The Lord’s Day”:
I was in the Spirit on the Lord’s day (Revelation 1:10).
This expression “Lord’s Day” is not the same as other expressions in Revelation rendered “day of the Lord.” The term translated “Lord’s” in Revelation 1 is not the same term used in the other references. This is a unique term of possession indicating that because of Christ’s resurrection, the first day of the week is a special day “belonging to the Lord.”
This same possessive term is used in 1 Corinthians 11:20 with reference to the “Lord’s supper.” This biblical ordinance is a supper “belonging to the Lord” in a special way. It is a supper set apart from other common suppers because it symbolizes the death of Christ. Similarly, the first day of the week is set apart from other common days because it is the day on which Christ arose.
We find clear examples in the New Testament of churches gathering together on the first day of the week:
On the first day of the week, when we were gathered together to break bread, Paul talked with them, intending to depart on the next day, and he prolonged his speech until midnight (Acts 20:7).
On the first day of every week, each of you is to put something aside and store it up, as he may prosper, so that there will be no collecting when I come (1 Corinthians 16:2).
While it is true that the expression “Lord’s Day” is used only once in the New Testament, and it is not explicitly connected to the first day of the week, testimony of early church leaders, including some friends of the Apostle John, confirm that the first day was called “The Lord’s Day.” For example, Ignatius, a companion of John said, “Let us no more Sabbatize, but let us keep the Lord’s day, on which our Life arose.” Likewise Iranaeus, a disciple of Polycarp who was a friend of John said, “On the Lord’s day every one of us Christians keep the Sabbath, meditating on the law, and rejoicing in the works of God.” Since John’s friends referred to the first day of the week as “The Lord’s Day,” there is no doubt to what John was referring in Revelation 1:10. So well was the Christian observance of the Lord’s Day known in the first centuries that pagan officials would ask, “Do you keep the Lord’s day?” as equivalent to the question, “Are you a Christian?”
So it is clear that for a Christian, the first day of the week should be a special day set apart for him because it is a day especially belonging to him.