“One who eats Matzah on Erev Pesach is as though he cohabited with his betrothed in his father in law’s home”. [Talmud Yerushalmi (Pesachim 10:1)]. While not cited by the Bavli, this quote is cited, or closely paraphrased, by many early halachic authorities (See for example Tur Orach Chaim 471). Indeed over the centuries this ambiguous ruling has been the subject of extensive discussion and debate.
In this brief essay I seek to address but two of the many obvious issues raised by this shocking statement. Firstly, why is one who eats matzah on Erev Pesach likened to an individual who is intimate with his affianced in the home of his father in law? Ordinarily, halachic rulings are presented in standard formulaic fashion. We are instructed in straightforward form about matters declared either prohibited (assur) or permitted (muttar), etc. What is meant by this evocative simile? Secondly, what kind of matzah is the Gemara referring to in this vague ruling? Is all matzah outlawed on the eve of Pesach? Or, is this restriction limited perhaps to only the variety necessary for seder consumption, i.e. shmura matzah?
With regards the second question there exists a dispute. Some (including The Meiri and Tosfos Rid in their respective commentaries to Pesachim 99b, amongst others) insist that only matzah suitable to fulfill the mitzvah on the night of Pesach may not be eaten on Erev Pesach. The Tashbetz (3:260) and Maharam Challavah (to Pesachim 49a) are part of a group who expand the ruling of the Yerushalmi and apply it even to matzah not classified as shmura.