Now after six days Jesus took Peter, James, and John his brother, led them up on a high mountain by themselves, and He was transfigured before them. His face shone like the sun, and His clothes became as white as the light. And behold, Moses and Elijah appeared to them, talking with Him. Mat 17:1-3
I believe the three disciples were seeing a vision of Jesus when He appears in His glory. When He walked the earth in His first advent, He looked like a nondescript man. Yes, the miracles He did revealed who He was to those who had ears to hear and eyes to see. But many convinced themselves that He was nothing but a nondescript man because He walked among us as a nondescript man.
But when Jesus returns, no one will have a question as to who He is:
Now I saw heaven opened, and behold, a white horse. And He who sat on him was called Faithful and True, and in righteousness He judges and makes war. His eyes were like a flame of fire, and on His head were many crowns. He had a name written that no one knew except Himself. He was clothed with a robe dipped in blood, and His name is called The Word of God. Rev 19:11-13
When He returns, He will appear glorious as befits the King of kings and Lord of lords. He will be awesome to behold, and I believe the earth will tremble at His appearing because of His glory.
Peter, James and John were seeing a prophetic vision of His glory as He will appear when He returns. When He returns, Moses and Elijah will be with Him. Moses is the prophet who instructed Israel in God’s Law – the Torah. Elijah is the prophet who worked miraculous signs by the power of the Spirit. Both will be with Jesus when He returns in His glory.
Now it may be that these two will actually return with Him. Moses went up to the top of a mountain to die, and no man was with him. It is said that God Himself buried him, but where his grave is, no one knows. Elijah was taken up to heaven without dying, as Enoch was. So in both cases, there is no dead body here on earth (or there might as well be no dead body here on earth).
But I believe the Scripture might be teaching something in addition, if the above is even correct – and I do not know for sure. Moses represents the Law or Torah of God – His Word. The Torah is part and parcel of God’s Word and has not been excised from it! Elijah represents the Spirit of God. The Torah and Spirit are one – for out of the abundance of the heart, the mouth speaks (Mat 12:34). The Word that God voiced, which Moses wrote down, came from His heart – His Holy Spirit.
I believe that the Word and the Spirit must be united in us, Messiah’s Body, before the return of the Lord, or at the very least, at His return, one of the first things He will do is unite His Body in Word and Spirit. It seems the Spirit- filled camp of believers in Messiah Yeshua are the first ones to throw His commandments out the window and live as they please without regard to the instruction of Scripture. Or the Torah- observant camp of believers in Messiah Yeshua deny the gifts of the Spirit, and do not walk by the very power of the Spirit that makes obedience possible! Both groups need to cross their camp boundaries and unite together into one Body of Messiah, so that the Head can return in His glory!