On the unity of John the Baptist and Elijah

[Machjo]

11 And they asked him, saying, Why say the scribes that Elias must first come? 12 And he answered and told them, Elias verily cometh first, and restoreth all things; and how it is written of the Son of man, that he must suffer many things, and be set at nought. 13 But I say unto you, That Elias is indeed come, and they have done unto him whatsoever they listed, as it is written of him.

Mark 9:11-13​

19 And this is the record of John, when the Jews sent priests and Levites from Jerusalem to ask him, Who art thou? 20 And he confessed, and denied not; but confessed, I am not the Christ. 21 And they asked him, What then? Art thou Elias? And he saith, I am not. Art thou that prophet? And he answered, No.

John 1:19-21​

1 And after six days Jesus taketh Peter, James, and John his brother, and bringeth them up into an high mountain apart, 2 And was transfigured before them: and his face did shine as the sun, and his raiment was white as the light. 3 And, behold, there appeared unto them Moses and Elias talking with him. 4 Then answered Peter, and said unto Jesus, Lord, it is good for us to be here: if thou wilt, let us make here three tabernacles; one for thee, and one for Moses, and one for Elias. 5 While he yet spake, behold, a bright cloud overshadowed them: and behold a voice out of the cloud, which said, This is my beloved Son, in whom I am well pleased; hear ye him. 6 And when the disciples heard it, they fell on their face, and were sore afraid. 7 And Jesus came and touched them, and said, Arise, and be not afraid. 8 And when they had lifted up their eyes, they saw no man, save Jesus only. 9 And as they came down from the mountain, Jesus charged them, saying, Tell the vision to no man, until the Son of man be risen again from the dead. 10 And his disciples asked him, saying, Why then say the scribes that Elias must first come? 11 And Jesus answered and said unto them, Elias truly shall first come, and restore all things. 12 But I say unto you, That Elias is come already, and they knew him not, but have done unto him whatsoever they listed. Likewise shall also the Son of man suffer of them. 13 Then the disciples understood that he spake unto them of John the Baptist.​

Matthew 17:1-13​

 

[Machjo]

How do you reconsile this apparent contradiction?

 

[Dexter Sinister]

How do you reconsile this apparent contradiction?

Couple of ways. Christian apologists will usually take the view that John the Baptist was not literally the person of Elijah, which is what the questioners expected, but came in the "spirit and power" of Elijah, referring to a passage in, I think, Malachi if my memory is correct, though I'd have to do a fair bit of digging to verify that.

Or you could take the view that the Bible is full of contradictions--which it is, I can point you to a list of over 400 of them if you're interested (most are pretty trivial), many of them with responses from serious Christians trying to reconcile them--but because it's mostly fiction it really doesn't matter. That's the view I take.