Revelation 1:8 (NIV)
8“I am the Alpha and the Omega,” says the Lord God, “who is, and who was, and who is to come, the Almighty.”
Revelation 21:6 (NIV)
6He said to me: “It is done. I am the Alpha and the Omega, the Beginning and the End. To him who is thirsty I will give to drink without cost from the spring of the water of life.
Revelation 22:13 (NIV)
13I am the Alpha and the Omega, the First and the Last, the Beginning and the End.