The Torah speaks of four children: One is wise, one is wicked, one is simple and one does not know how to ask.

The wise one, what does he say? "What are the testimonies, the statutes and the laws which the L-rd, our G‑d, has commanded you?" You, in turn, shall instruct him in the laws of Passover, [up to] `one is not to eat any dessert after the Passover-lamb.'

The wicked one, what does he say? "What is this service to you?!" He says `to you,' but not to him! By thus excluding himself from the community he has denied that which is fundamental. You, therefore, blunt his teeth and say to him: "It is because of this that the L-rd did for me when I left Egypt"; `for me' - but not for him! If he had been there, he would not have been redeemed!"

The simpleton, what does he say? "What is this?" Thus you shall say to him: "With a strong hand the L-rd took us out of Egypt, from the house of slaves."

As for the one who does not know how to ask, you must initiate him, as it is said: "You shall tell your child on that day, `It is because of this that the L-rd did for me when I left Egypt.'"


haggadah Section: -- Four Children
Source: http://www.chabad.org/holidays/passover/pesach_cdo/aid/661624/jewish/English-Haggadah.htm