This is quite a remarkable statement in the Greek language. The alpha and omega are the first and last letters of the Greek alphabet. From an alphabet you make words, and Jesus Christ is called the "Word of God" — the full revelation and intelligent communication of God. He is the only alphabet you can use to reach God, my friend. The only language God speaks and understands is the language where Jesus is the Alpha and the Omega and all the letters in between. He is the "A" and the "Z," and He is the "ABC."
If you are going to get through to God the Father, you will have to go through the Son, Jesus Christ. Here the emphasis is upon the beginning and the end. In the original Greek, the Omega is not spelled out as is the Alpha. Why? Because Christ is the beginning, and the beginning is already completed. But the end is yet to be; so He didn't spell out the Omega in this instance. One day He will complete God's program. This is a very interesting detail in the Greek text.
"The beginning and the ending" refers to the eternity of the Son and His immutability. Concerning this, Hebrews 13:8 says, "Jesus Christ the same yesterday, and to-day, and for ever." When it says that He is the same, it does not mean that He is walking over yonder by the Sea of Galilee today. He is not. But it means that in His attributes He is the same. He has not changed. He is immutable. Since He is the beginning and the ending, He encompasses all time and eternity.
—From Edited Messages on Revelation ©1994