A.T. Robertson Commentary Revelation 22:13

"I am the Alpha and the Omega, the first and the last, the beginning and the end." — Revelation 22:13 (ASV)

I am the Alpha and the Omega (Εγω το Αλφα κα το Ο). Applied to God in 1:8; 21:6, and here alone to Christ, crowning proof in this book of Christ's deity. So in 21:6 God is termed, as Christ is here, η αρχη κα το τελος (the beginning and the end), while ο πρωτος κα ο εσχατος (the first and the last) is applied only to Christ (1:17; 2:8). Solemn assurance is thus given that Christ is qualified to be the Judge of verse 12 (cf. Matthew 25:31–46). In Heb 12:2 Jesus is the αρχηγος κα τελειωτης της πιστεως (the author and finisher of faith). Christ was the Creator of the universe for the Father. So now he is the Consummation of redemption.