Matthew 17:11

And Jesus answered and said unto them, Elias truly shall first come, and restore all things.

The saying belongs to the transfiguration narrative of Matthew 17:1-18, which moves from standing with Christ on the mount of transfiguration beholding His beauty and becoming radiant in the presence of His glory, to going down into the plain where souls enslaved by Satan are waiting for the word of faith and prayer to set them free. It promises that Elijah must come first, before the promised events and the kingdom of Christ, to restore all things. When the disciples saw Elijah on the mount they supposed this prophecy was being fulfilled and that Christ's kingdom was about to be established on earth. The Elijah who had already come was John the Baptist, who fulfilled the restoring work by preparing people for the Lord, though the people did not recognize him and mistreated him.