Alpha

Alpha is the first letter of the Greek alphabet, and in Revelation Jesus uses it as a name. “I am Alpha and Omega, the beginning and the ending,” he says, then adds “the first and the last.” The same words close the book in chapter 21, where the speaker promises water from the fountain of life, freely given. Isaiah had already heard the LORD speak this way: “I am the first, and I am the last; and beside me there is no God.” One voice holds the start of everything and its end. Begin with Revelation 1:8, then compare Isaiah 44:6.

6 verses

Isaiah

Isaiah 41:4

Who hath wrought and done it, calling the generations from the beginning? I the LORD, the first, and with the last; I am he.

Isaiah 44:6

Thus saith the LORD the King of Israel, and his redeemer the LORD of hosts; I am the first, and I am the last; and beside me there is no God.

Isaiah 48:12

Hearken unto me, O Jacob and Israel, my called; I am he; I am the first, I also am the last.

Revelation

Revelation 1:8

I am Alpha and Omega, the beginning and the ending, saith the Lord, which is, and which was, and which is to come, the Almighty.

Revelation 1:11

Saying, I am Alpha and Omega, the first and the last: and, What thou seest, write in a book, and send it unto the seven churches which are in Asia; unto Ephesus, and unto Smyrna, and unto Pergamos, and unto Thyatira, and unto Sardis, and unto Philadelphia, and unto Laodicea.

Revelation 21:6

And he said unto me, It is done. I am Alpha and Omega, the beginning and the end. I will give unto him that is athirst of the fountain of the water of life freely.

From Smith's Bible Dictionary

William Smith, 1884

(A), the first letter of the Greek alphabet. With Omega, the last letter, it is used in the Old Testament and in the New to express the eternity of God, as including both the beginning and the end. (Revelation 1:8,11; 21:6; 22;13; Isaiah 41:4; 44:6) hence these letters became a favorite symbol of the eternal divinity of our Lord, and were used for this purpose in connection with the cross, or the monogram of Christ (i.e. the first two letters, ch and r, of Christ’s name in Greek). Both Greeks and Hebrews employed the letters of the alphabet as numerals.