The Jewish religious scholars expected Elijah the Prophet to appear as a forerunner of the Messiah as detailed by the prophet Malachi,"Behold, I will send you Elijah the prophet before the coming of the great and dreadful day of the Lord.
And he will turn the hearts of the fathers to the children, and the hearts of the children to their fathers, lest I come and strike the earth with a curse"
Malachi 4:5,6