“Look!” The Greek word is idou (#2400 ἰδού), and it is used to get our attention. See commentary on Matthew 1:20 (“Look!).
“Moses and Elijah.” To properly understand the Transfiguration, we must recognize that it was “a vision;” a spiritual experience. Moses and Elijah were not there in person, but only as part of the vision. Matthew 17:9 clearly calls the experience a “vision.” The Greek word translated “vision” is horama (#3705 ὅραμα), and besides here, it is used of visions in Acts 9:10, 12; 10:3, 17, 19; 11:5; 12:9; 16:9-10 and 18:9. Many Bible versions translate the Greek text as “vision” (cp. HCSB; Darby; ESV; KJV; NAB; NASB; NET; NKJV; RSV; YLT). The NIV is not as clear, saying, “What you have seen.”
In the revelation experience at the Transfiguration, Jesus was transported to the future, to the exalted state he would have after his resurrection. The Bible says, “and his face shone like the sun” (Matt. 17:2), which is exactly how it was after he was glorified when he appeared to the Apostle John (Rev. 1:16); in fact, the promise of God is that after the resurrection, all the righteous people “will shine like the sun” (Matt. 13:43). And just as on that mountain that day Jesus was not yet actually glorified, neither were Moses and Elijah actually there in person. But the promise was that if Jesus succeeded in being a sinless sacrifice for the sins of mankind, he would be glorified, and also Moses and Elijah would really be raised from the dead in the Resurrection of the Righteous (Luke 14:14; Acts 24:15). The vision God gave Christ would one day be a reality if Jesus endured to the end, which he did.
God gave Jesus a revelation vision of what things would be like in the future for the same reason that He gave many prophets a vision of the future—for encouragement, strength, and hope. God gave Christ the vision to help prepare him for “his departure,” and the subject that “Moses” and “Elijah” discussed with Jesus was his death (Luke 9:31). Jesus was not the only one to whom God gave courage and hope by giving them a revelation vision of the future. Prophets such as Isaiah, Ezekiel, and Zechariah, had very clear revelations of the future, and so did New Testament figures such as Paul and John. So while what God did for Jesus at the Transfiguration was very graphic, it was not materially different from what God had done to encourage others. This should show us the importance of having a clear hope, and building hope in the lives of others.
Although it is commonly taught that Moses and Elijah appeared in person at the Transfiguration, they were only there in a vision, not in reality. The Bible teaches that when a person dies, he is dead in every way, and not alive in any form until God raises him from the dead at the Rapture or one of the resurrections [see Appendix 4: “The Dead are Dead”].
Another clear reason that Moses and Elijah could not have been on the Mount of Transfiguration is that they could not be alive before Christ paid the price for their sin. If Moses and Elijah could get up from the dead and be in a glorified state before Jesus paid for their sin, then anyone could be raised before Jesus paid for their sin. In that case, there would have been no point in Jesus dying. Some people say, “Well, the body does die, but the soul lives on.” That cannot be correct. If the “souls” of Moses and Elijah could be as glorious as they were on the Mount of Transfiguration before Christ died for sin, then anyone’s soul could live with God in a glorified state before Christ died, so we again arrive at the conclusion that there would have been no need for the death and resurrection of Christ. The Bible is clear that until the death of Christ, no one’s sin had been paid for, which is why no one who had died could be alive in any form before the death and resurrection of Christ.
Another reason we know it was not really Moses and Elijah on the Mount of Transfiguration with Jesus is that 1 Corinthians 15:23 says that Christ is the “firstfruits” from the dead. However, if Moses and Elijah were alive on the Mount of Transfiguration in glorified bodies, then they were alive and glorified before Jesus got up from the dead. In that case, Jesus would not have been the “firstfruits” from the dead, but Moses, Elijah, or even some other godly person who died before they did would have been the real “firstfruits.” That cannot be the case. Moses and Elijah were not “firstfruits” before Jesus; they were a vision of the future.
Another reason that we know the Transfiguration event was a “vision” was that neither Jesus nor the Apostles would have known Moses and Elijah by sight. So part of the revelation vision was that Jesus, Peter, James, and John actually understood who and what they were seeing. God did not need to say, “Hey everyone, this is Moses and Elijah.” It often happens that when God gives someone a revelation vision, He also gives him an understanding of what he is seeing in the vision, and that is what happened on the Mount of Transfiguration.
It is sometimes taught that Elijah could be on the Mount of Transfiguration because he never died, but was taken directly up to heaven by God. This idea comes from 2 Kings 2:11, which says that Elijah “goeth up in a whirlwind, to the heavens” (YLT). To understand this verse we need to understand that the word “heaven” (“heavens” in the Hebrew), can refer either to the dwelling place of God or to the air above the earth. That is why the Bible speaks of the birds of heaven (often translated “birds of the air), the rain from heaven, and the snow from heaven (2 Sam. 21:10; Deut. 11:11; Isa. 55:10). Elijah was taken by God’s whirlwind into the air, and in that manner moved away from Elisha, who could then take over his position as head prophet. Culturally, Elisha could never replace Elijah as long as Elijah was there, so God took Elijah away in a dramatic fashion.
The prophets with Elisha knew that God did not take Elijah to heaven, but to somewhere else on earth, and they begged Elisha to let them go look for him, which he finally allowed them to do. Of course they never found Elijah—God made sure of that, and Elisha stepped into the leadership role over the prophets of Israel. In any case, Moses and Elijah appeared in a vision at the Transfiguration, and even if Elijah never died that does not explain how Moses could have been there.
Elijah eventually died somewhere on earth. We know that because the wages of sin is death, and Elijah was not sinless; no person has ever lived a sinless life except Jesus Christ. If God could take Elijah to heaven and give him everlasting life without Jesus dying for his sins, then God could have taken any good person to heaven before Christ paid for their sins, and the death of the Christ would have been unnecessary. In summary, Moses and Elijah were visions. If Moses and Elijah could have been alive in glorified bodies before Christ died, then Christ did not need to die.