The letters recognize that each church is composed of both believers and church-going unbelievers. Church (Ἐκκλησίας [Ekklēsias] ) is a compound word made up of from or out (ἐκ [ek] ) and I call (καλέω [kaleō] ) and is used in a variety of contexts:
This word [ecclesia] translated church or assembly is found in at least four important meanings in the New Testament. It is used (1) to mean an assembly of people. In this sense it has no special theological meaning. It can refer to Israel as a gathered people in the wilderness (Acts Acts 7:38) or a regular assembly of citizens (Acts Acts 19:39) or a group of people gathered for religious worship (Heb. Heb. 2:12). (2) The same word is used for an assembly of Christians in a local church (Acts Acts 8:1, Acts 8:3; Acts 11:22, Acts 11:26) and in the plural for a group of such churches (1Cor. 1Cor. 16:19; Gal. Gal. 1:2). Each assembly or church has a local gathering composed of professed Christians. That all in the assembly are not necessarily true believers is clear from the messages to the seven churches of Asia (Rev. Rev. 2:1+-Rev. 3:22+). (3) Ecclesia is also used of the total of professing Christians without reference to locality and is practically parallel in this sense to Christendom (Acts Acts 12:1; Rom. Rom. 16:16; 1Cor. 1Cor. 15:9; Gal. Gal. 1:13; Rev. Rev. 2:1-29+, Rev. 3:1-22+; etc.). The same word is used (4) of the body of Christ, composed of those baptized by the Holy Spirit into the church (1Cor. 1Cor. 12:13). Ecclesia used in this connection becomes a technical word referring to the saints of this age.1It is important to recognize that the letters to these seven churches use the term church in the sense of a local gathering of professing believers. It is not used in a technical sense to describe all those who are known to have been born againthe true body of Christ (Luke Luke 15:24, Luke 15:32; John John 3:3, John 3:7; Gal. Gal. 6:15; 1Pe. 1Pe. 1:3, 1Pe. 1:23; 1Jn. 1Jn. 2:29; 1Jn. 3:9; 1Jn. 5:1, 1Jn. 5:18). If we fail to understand that the letters address both believers and church-going unbelievers, then the promises attending each letter will be misconstrued.2
[the letters] involve the visible church rather than the invisible Church. The latter is the Body of Messiah, composed of all true believers since Pentecost. It is sometimes referred to as the Universal Church. But the visible church is the local body or local church, which may have both believers and unbelievers. It includes all professing believers whether they really are or not.3The omniscience and piercing gaze of Jesus is evident by His detailed knowledge of the condition of each church. Jesus knows their works (Rev. Rev. 2:2+, Rev. 2:9+, Rev. 2:13+, Rev. 2:19+; Rev. 3:1+, Rev. 3:8+, Rev. 3:15+). Know (Οἶδα [Oida] , Rev. Rev. 2:2+) expresses the Lords self-claim of knowledge in each of the seven messages in contrast to γινώσκω [ginōskō] (I know), which speaks of progress of knowledge, oida reflects full or complete knowledge. It depicts absolute clearness of mental vision, which photographs all facts of life as they pass. It, not ginōskō, is always the word used of Christs knowledge in Revelation.4
We call the contents of these chapters Epistles; but they are not so much messages from an absent Lord as sentences of a present Judge, engaged in the solemn act of inspection and decision.5
5 J. A. Seiss, The Apocalypse: Lectures on the Book of Revelation (Grand Rapids, MI: Zondervan Publishing House, 1966), 67.