So when jesus tells the disciples that the Spirit of Elijah has already returned and they didn't know him, you're disageeing?"
I disagree with your interpretation of what the "spirit of Elias" is. The Lord Jesus Christ never taught the concept of reincarnation.
First off, the angel Gabriel told Zacharias (John the Baptist's father) that his son would go before the Lord "in the
spirit and
power of Elias" (Luke 1:17)
Notice that the angel did not say that John the Baptist would
be the prophet Elijah reborn, but that he would bear the "spirit" and "power" of Elias.
Second, John the Baptist himself, claimed to
not be Elias when asked. "Art thou Elias? And he saith,
I am not." (John 1:21)
I understand that Elias is the Greek form of the Hebrew name Elijah, but I want to draw your attention to that fact that these two verses discussed two different things.
The first mentioned by the angel was the "spirit and power of Elias (Elijah)" or in other words, his
authority and the second was a question concerning the prophecy of Elijah returning to the Earth before the coming of the Kingdom of God.
To better understand this concept of having the authority of Elias, we need more instruction from the Master.
After John the Baptist's disciples came questioning the Lord He revealed some amazing details about John the Baptist, which were:
1.) He was
more than just a prophet and one of the justifications the Lord gave for this distinction was that John the Baptist fulfilled the words of prophecy, which were,
"For this is he, of whom it is written, Behold, I send my
messenger before thy face, which shall
prepare thy way before thee." (Matthew 11:10)
John the Baptist was more than a prophet because he was sent to Earth with a particular mission, to be the herald of the Lord and to prepare His people for His coming.
2.) That John the Baptist was the
greatest of all those "born of women", save the Lord Jesus Christ Himself (the least in the kingdom of heaven). (Matthew 11:11)
This would of course also rule out both Adam and Eve since neither of them were born of women.
3.) John the Baptist was the culmination of the prophecies of the Mosaic Law and the Prophets. (Matthew 11:12-13)
4.) Receiving the testimony of John the Baptist, that the Law and the Prophets were fulfilled in the arrival of the Lord Jesus Christ, and that all must rely on Him is to receive the witness of the "spirit or power or authority of Elias".
"And if ye will receive it, this is Elias, which was for to come." (Matthew 11:14)
Another way of saying that a person comes in the "spirit and power of Elias" is to refer to them by it as a title.
John the Baptist was
an Elias. He was sent to Earth to be a
forerunner or a
preparer of things to come. In this light both Noah and the angel Gabriel can accurately be referred to as Elias.
The Lord revealed even more concerning what it could mean to be an Elias after His disciples asked Him concerning why Elias should come first, before the Kingdom of God on Earth. He said,
"Elias truly shall first come, and
restore all things." (Matthew 17:11)
An Elias can also be someone who restores something that has been lost. Either doctrine, scripture, priesthood, etc.
By this distinction the Lord Jesus Christ Himself could be described as an Elias, for He restored or fulfilled the Law and the prophets.
However, due to the future tense used by the Lord in Matthew 17:11, that Elias "shall" first come and restore all things before the coming of the Kingdom of God upon the Earth, I am convinced that neither the ministry of John the Baptist nor the appearance of Elijah (Elias) on the Mount of Transfiguration were what He was referring to here and He was looking forward to a future time.
It is similar to in the Lord's Prayer when He said, "Thy kingdom come.", which is a reference to a future event, rather than to His mortal ministry.
I am convinced that the coming of Elias awaited by the Jews is in reference to his coming to the Earth sometime leading up to the Millennial Reign of Christ after the First Resurrection of the Just.