Why
Matthew 17:3
Suddenly, Moses and Elijah appeared to them, talking with Him.
Matthew 17:4
Then Peter said to Jesus, "Lord, it's good for us to be here! If You want, I will make three tabernacles here: one for You, one for Moses, and one for Elijah."
Matthew 11:14
if you're willing to accept it, he is the Elijah who is to come.
Matthew 27:47-49
47
When some of those standing there heard this, they said, "He's calling for Elijah!"
48
Immediately one of them ran and got a sponge, filled it with sour wine, fixed it on a reed, and offered Him a drink.
49
But the rest said, "Let's see if Elijah comes to save Him!"
Malachi 4:5
Look, I am going to send you Elijah the prophet before the great and awesome Day of the LORD comes.
Malachi 4:6
And he will turn the hearts of fathers to [their] children and the hearts of children to their fathers. Otherwise, I will come and strike the land with a curse."
Mark 9:11
Then they began to question Him, "Why do the scribes say that Elijah must come first?"
John 1:21
"What then?" they asked him. "Are you Elijah?" "I am not," he said. "Are you the Prophet?" "No," he answered.
John 1:25
So they asked him, "Why then do you baptize if you aren't the Messiah, or Elijah, or the Prophet?"