the Lord’s day: In the Roman world, this term referred to celebrations for Caesar. Christians, however, used it for their weekly worship, celebrating the resurrection of Jesus. The earliest Christians worshiped in Jewish synagogues on the Sabbath, the last day of the week (Acts 18:4). By the time of Revelation, they were no longer allowed in synagogues and gathered on the first day of the week, which marked the resurrection (see study note on Luke 24:1; see also Acts 20:7).
The loud voice like a trumpet blast announced the Lord’s coming.