When the Temple stood in Jerusalem more than a thousand years ago, the most important sacrifice was the pesach, or lamb sacrifice. The great sage Hillel would put the lamb meat in a sandwich made of matzah, along with some of the bitter herbs. While Jews no longer make sacrifices, we honor this custom by eating a sandwich of the remaining matzah and bitter herbs. Many will also include charoset in the sandwich to remind us again of the sweetness of freedom.

haggadah Section: Koreich
Source: JewishBoston.com