Matthew 17:10-13

And His disciples asked Him, saying, “Why then do the scribes say that Elijah must come first?” Jesus answered and said to them, “Indeed, Elijah is coming first and will restore all things. But I say to you that Elijah has come already, and they did not know him but did to him whatever they wished. Likewise the Son of Man is also about to suffer at their hands.” Then the disciples understood that He spoke to them of John the Baptist.