The traditional Haggadah speaks of "four sons" – one who is wise, one who is wicked, one who is simple, and one who does not know to ask. This is based upon the rabbis of the Jerusalem Talmud finding four references in the Torah to responding to your son who asks a question. Each of these sons phrases his question about the seder in a different way. The Haggadah recommends answering each son according to his question, using one of the three verses in the Torah that refer to this exchange.