Revelation 19:9

The person who now spoke to John appears to be the same angel who had been guiding him thorough the revelation concerning Babylon (cf. Revelation 17:1; Revelation 17:15). He instructed John to write again (cf. Revelation 1:11; Revelation 1:19; Revelation 14:13; Revelation 21:5), this time another beatitude (cf. Revelation 14:3). This blessing gives Tribulation saints an additional motivation to remain faithful. Those invited to the Lamb’s marriage supper include His friends as well as the bride (cf. Revelation 3:20). This implies the presence of other believers besides church saints at this celebration. Those invited to the supper will include the bride and other believers who are not members of the church. These other believers would be Tribulation martyrs and believers who will live through the Tribulation and enter the Millennium alive (cf. Revelation 12:13-17; Revelation 20:4-5; Matthew 22:11-14; Matthew 25:1-13). They may also include Old Testament saints who will experience resurrection at the beginning of the Millennium (cf. Isaiah 26:19; Daniel 12:2).

The angel concluded with the final sentence, "These are true words of God" (cf. Revelation 22:6; Revelation 22:8-9). He could have been referring to what we read in the first part of this verse. [Note: Hughes, p. 201.] However since this statement concludes all that this angel had revealed since Revelation 17:1, it seems better to take it as referring to all the intervening revelation. [Note: Düsterdieck, p. 454; Alford, 4:725.]