The extra cup of wine on the table is the Cup of Elijah. There is a story that Elijah, a great teacher who lived long ago, said that he would return in each generation disguised as someone poor or oppressed and come to people's door to see how he would be treated. For that reason, we open the door and invite Elijah to come in with this song: 

Eliahu hanavi, eliahu hatishbi

eliahu, eliahu, eliahu hagiladi

Bimhera b'yameinu yavo elenu

Im Mashiach ben David, Im Mashiach ben David

Eliahu hanavi, eliahu hatishbi

eliahu, eliahu, eliahu hagiladi


haggadah Section: Hallel