And a voice came out of the throne, saying. ἐκ "out of," is found in א, P, 1, 34, etc.; ἀπό, "forth from," is supported by A, B, C, etc.; while B reads οὐρανοῦ, "heaven," instead of θρόνου, "throne."
Alford suggests that the direction rather than the source of the voice is intended. It is impossible to say to whom the voice should be attributed (cf. Revelation 10:4, Revelation 10:8, etc.). As an invitation to the Church to praise God, we might expect the voice to be that of one of the elders.
Praise our God, all ye his servants, and ye that fear him, both small and great, א, C, P, omit the first "and," thus reading: "ye his servants, ye that fear him," etc. The first words are a repetition of the "Hallelujah" of Revelation 19:1.
The following phrases are found in Psalms 134:1; Psalms 115:13.