It is traditional at this point in the seder, to sing songs of praise. This is one of my favorites for this event.

Hinei ma tov umanaim

Shevet achim gam yachad

Hinei ma tov umanaim

Shevet achim gam yachad

Behold how good and

How pleasant it is

For brothers to dwell together


haggadah Section: Hallel
Source: http://www.lyricstime.com/shalom-jerusalem-hinei-ma-tov-behold-how-good-lyrics.html