Occasionally someone may talk about the Lord’s Day assembly, referring to the Sunday gathering of the church. Many writers use the phrase “the Lord’s day” to refer to the first day of the week. At least one writer has stated that by the time the Revelation was written Sunday had come to be known as the Lord’s day. Of course, he makes this statement with no proof of its validity. Just what is the Lord’s day?
Many people assume we call Sunday the Lord’s day because it is so designated in scripture. That assumption would be wrong. Sunday is frequently called “the first [day] of the week.” The first recorded instance of it specifically and indisputably being used to refer to Sunday did not occur until over a hundred years after John wrote the Revelation. In fact, the phrase appears only once in the Bible. Revelation 1:10 says, “I was in the Spirit on the Lord's day, and heard behind me a great voice, as of a trumpet.” There are at least three possible interpretations of this passage.
One, of course, is that John saw all of his visions on one Sunday. As proof, some point out the similarity of the phrases “the Lord’s supper” (1 Cor 11:20, also a unique usage) and “the Lord’s day.” Since the Lord’s supper was observed at a minimum on the first day of the week, the similar phrase must relate to the same day, the day on which Jesus rose from the dead. This ignores the possibility (probability) that the Lord’s Supper was observed more frequently. (Acts 2:46 may refer to daily observance.) Others point out that early Christian writers from at least 170 AD onward used the phrase to refer to Sunday. That, however, may simply be because they also made an assumption based solely on their interpretation of Revelation 1:10.
The second most common view is that John was not talking about the specific day of his visions. Instead, he may have said, “I was, in the Spirit, on the Lord’s Day [meaning the day of God’s judgement].” This would be like saying that although he was on the Isle of Patmos he was, in the spirit, in Jerusalem. This is based on the idea that “the day of the Lord” is commonly used in prophecy to refer to any day in which God brings punishment or judgement on the earth. It is so used in Joel (2:31)/Acts (2:20) to refer to the beginning of the church. Thus John may be speaking of the subject of the vision, rather than the date on which he saw it. The problem is that the phrasing is wrong. In English, the day of the Lord and the Lord’s day virtually mean the same thing. In the Greek, however, the scriptures consistently speak of the day of the Lord (hamartia kurios) but only once of the Lord’s day (kuriakos hamartia). If John meant to relate his vision to others of “the day of the Lord” he would most likely have phrased it in the same way the others did.
The third possibility is related to the first. John may have been speaking of the date of his vision, but thinking in his native (Jewish) idiom. That would make the Lord’s day the Sabbath (seventh) day rather than what early Christian writers called the eighth day/first day. As with choice one, there is little real support for this option. Nowhere else in scripture or Jewish literature is Sabbath referred to as the Lord’s day. The only support for this idea is that John was Jewish. If any day were to be designated as belonging to the Lord, it would most likely be the Sabbath. This was the day of rest, based on God’s rest. It was the day given to the Jewish people by God. Having grown up with this knowledge, it is only proper that as an old man, as most assume he was, John would revert to his established patterns of thought.
We have no way of knowing exactly what John meant by “the Lord’s day.” Because this is the only, and ambiguous, use of the phrase, we should be careful of using it in an unambiguous way to refer only to Sunday, although Christian writers of subsequent centuries did so. Perhaps we should not use the phrase at all. We know Saturday was called Sabbath; we know Sunday was called the first of the week. Maybe we should just leave it at that.