Revelation 1:8

God confirmed the preceding forecast with a solemn affirmation of His eternity and omnipotence. Alpha and omega are the first and last letters of the Greek alphabet and signify here God’s comprehensive control over all things including time. This is probably a merism, a figure of speech in which two extremes represent the whole. John strengthened this point further with present, past, and future references (cf. Revelation 4:8; Revelation 11:17; Hebrews 13:8). He is the originator and terminator of all things. God is not only Lord of the future. He is also powerful enough to bring what John just predicted to pass. He is the "Almighty."

"A weighing of evidence, especially in light of the OT ’flavor’ of the expression and a recollection that the Father in the OT refers to Himself as ’I am’ (i.e., the Tetragrammaton, Exodus 3:14; cf. Isaiah 48:12), tips the balance ever so slightly to the side of concluding that God the Father speaks in Revelation 1:8. . . .

"God’s declaration in Revelation 1:8 thus ends with a note of authority. The omnipotent one will surely implement what His prophet has predicted by way of future judgment." [Note: Thomas, Revelation 1-7, pp. 80, 81. Cf. Harris, p. 182.]

John frequently used "Almighty" as a key name for God in Revelation (Revelation 1:8; Revelation 4:8; Revelation 11:17; Revelation 15:3; Revelation 16:7; Revelation 16:14; Revelation 19:6; Revelation 19:15; Revelation 21:22).

This whole introduction points to the main event of the following revelation, the return of Jesus Christ at His second coming (Revelation 19:11-16). It also presents the triune God as Lord of time (past, present, and future), faithful to His promises, and powerful enough to bring these events to pass. In Genesis, Moses also emphasized God’s power and faithfulness more than any other of His attributes. The last Bible book stresses these qualities of God as does the first Bible book.