Pesachim 99 - No eating till evening

In the afternoon before the Seder, one should not eat until night (and Seder) comes. What is the purpose of this rule? He cannot eat anything anyway! If it is chametz that he wants to eat, it is already prohibited in the second half-day before Passover. And if it is matzah, then it is already prohibited because one should not eat matzah the day before Seder - to welcome its taste at the Seder. Guess? The answer is that one should not eat egg matzah (called rich matzah) or too many vegetables. 

Even the poorest among the Jews should eat while reclining, imitating rich and free people. Some say that he should recline during the first two wine cups while discussing being a slave, and some - that he should recline during the last two wine cups while discussing becoming free. To fulfill both views, he reclines for all four cups.

All should have four cups of wine. Even the poorest person supplied with the communal charity has to be provided with four cups of wine.

Art:  Young Wine Taster by Philippe Mercier