Revelation 1:4

John] We know of no John, except the Apostle, who had authority to address seven Churches. Seven] the number which signifies completeness. These seven Churches stand also for the whole Church of Christ. Asia] i.e. the Roman province of that name, which was the western part of what is now called Asia Minor. It included Mysia, Lydia, Caria, part of Phrygia, and islands off the coast.

Which is, etc.] i.e. the Eternal: cp. Exodus 3:14.

Seven Spirits] i.e. the Holy Spirit in His complete working: cp. Revelation 4:5; Revelation 5:6.