The disciples asked Him, “Why then do the scribes say that Elijah must come first?” Jesus replied, “Elijah does indeed come, and he will restore all things. But I tell you that Elijah has already come, and they did not recognize him, but have done to him whatever they wished. In the same way, the Son of Man will suffer at their hands.” Then the disciples understood that He was speaking to them about John the Baptist.
And he will turn the hearts of the fathers to their children, and the hearts of the children to their fathers. Otherwise, I will come and strike the land with a curse."
Significance
Coming down from the Transfiguration — where Elijah himself has just appeared with Moses — the disciples ask why the scribes teach "that Elijah must come first" (Matt 17:10), a scribal expectation drawn directly from Malachi 4:5-6, the last word of the OT: "Behold, I will send you Elijah the prophet before the coming of the great and awesome Day of the LORD." Jesus affirms the promise ("Elijah does indeed come, and he will restore all things," 17:11 — echoing Malachi's "turn the hearts" reform of 4:6) and then declares its fulfillment: "Elijah has already come, and they did not recognize him" (17:12), so that "the disciples understood that He was speaking to them about John the Baptist" (17:13). The link is Promise-Fulfillment — not typology in this node — because the warrant is a dominical pronouncement that the named, stated promise of Elijah's coming has now arrived in a specific person; the analogical Elijah-office trajectory is the separate concern of TT 050. This is the distinctly Matthean parallel to Mark 9:11-13: Matthew alone closes with the disciples' explicit recognition (17:13), and alone preserves Jesus' "restore all things" gloss on Malachi 4:6. Jesus binds the herald's fate to His own — "they did... whatever they wished. In the same way, the Son of Man will suffer at their hands" (17:12) — so that the forerunner's rejection foreshadows the cross. The deletion-test telos: Malachi sealed the canon with four centuries of waiting for a herald who would precede the Lord's coming; Matthew reveals that the One the disciples have just beheld shining "like the sun" (17:2) is that very Lord, His advent already announced and His glory already unveiled — the Christ for whom Israel ached is not merely foreshadowed but present, recognized, and supremely worth beholding.
Found via
Anchor-Text Network (Malachi 3:1 — Behold I Send My Messenger)