Mark 9:9-13

And as they were coming down the mountain, he charged them to tell no one what they had seen, until the Son of Man had risen from the dead. So they kept the matter to themselves, questioning what this rising from the dead might mean. And they asked him, “Why do the scribes say that first Elijah must come?” And he said to them, “Elijah does come first to restore all things. And how is it written of the Son of Man that he should suffer many things and be treated with contempt? But I tell you that Elijah has come, and they did to him whatever they pleased, as it is written of him.”