The Scofield Bible Commentary, by Cyrus Ingerson Scofield, [1917], at sacred-texts.com
angel
(See Scofield) - (Heb 1:4).
sins
Sin
(See Scofield) - (Rom 3:23).
isle
From (Rev 1:1) to (Rev 1:20), the Seer is on the earth, looking at the vision of Christ.
From (Rev 2:1) to (Rev 3:22), he is on the earth looking forward through the church-age.
From (Rev 4:1) to (Rev 11:1), he is "in the Spirit" (Rev 4:2); (compare (Eze 3:12-14) observing things in heaven and on earth.
From (Rev 11:1) to (Rev 11:12), he is in Jerusalem with the two witnesses.
From (Rev 11:13) to the end, he is in heaven observing and recording things in heaven and upon the earth.
voice
The theophanies. (Rev 1:9-20); (Gen 12:7).
hell
Hades.
(See Scofield) - (Luk 16:23).
hereafter
Things that are to be after these, that is, after the churches.
angels
The natural explanation of the "messengers" is that they were men sent by the seven churches to ascertain the state of the aged apostle, now an exile in Patmos (compare (Phi 4:18) but they figure any who bear God's messages to a church.
churches
The messages to the seven churches have a fourfold application:
(1) Local, to the churches actually addressed;
(2) Admonitory, to all churches in all time as tests by which they may discern their true spiritual state in the sight of God;
(3) Personal, in the exhortations to him "that hath an ear," and in the promise "to him that overcometh"; and
(4) Prophetic, as disclosing seven phases of the spiritual history of the church from, say, A.D. 96 to the end.
It is incredible that in a prophecy covering the church period, there should be no such foreview. These messages must contain that foreview if it is in the book at all, for the church does not appear after (Rev 3:22). Again, these messages by their very terms go beyond the local assemblies mentioned. Most conclusively of all, these messages do present an exact foreview of the spiritual history of the church, and in this precise order.
Ephesus gives the general state at the date of the writing; Smyrna, the period of the great persecutions; Pergamos, the church settled down in the world, "where Satan's throne is," after the conversion of Constantine, say A.D. 316. Thyatira is the Papacy, developed out of the Pergamos state: Balaamism (worldliness) and Nicolaitanism (priestly assumption) having conquered. As Jezebel brought idolatry into Israel, so Romanism weds Christian doctrine to pagan ceremonies. Sardis is the Protestant Reformation, whose works were not "fulfilled." Philadelphia is whatever bears clear testimony to the Word and the Name in the time of self-satisfied profession represented by Laodicea.
mystery
(See Scofield) - (Mat 13:11).