The Shulhan Aruch rules (454:4) that one who eats Massa Gezula (Stolen Massa) on Pesah does not fulfill his obligation. One cannot do a Misva with an item obtained illicitly. The Be’ur Halacha poses the question whether this principle also applies to the transgression of carrying on Shabbat, in a place where there is no Eruv. For example, this year the Seder Night is on Shabbat. If one brought a package of Massot to the Seder from the public domain into his house, he has violated the Shabbat. Can one fulfill the obligation of Massa by eating those Massot? The Be’ur Halacha concludes that one does, in fact, fulfill the Misva. He explains that in the case of stolen Massa, the Massa itself was obtained via a transgression, whereas in this case, the Massa itself is permissible; it was merely transported in violation of the Halacha.
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Hacham Ben Sion discusses a related question, posed by the Sefat Emmet (Rav Yehuda Aryeh Leib Alter of Ger, 1847-1905) . Must the head of the household formally make a Kinyan (Transaction) to give the Massot to his guests at the Seder? Is the Halacha of Massa comparable to the Halacha of Lulav, in which a person must give his Lulav as a gift to his friend who wants to use it on the first day of Succot? He answers that with regard to Massa, the very fact that he lets his guests eat the Massa indicates that he intends for it to be theirs. There is no possibility of merely borrowing food items. On the other hand, letting someone use a Lulav without formerly transferring ownership, may merely indicate lending and not a gift.
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The Mishna Berura points out that if one bought Massa and did not yet remit payment, it is considered Massa Gezula from the point the seller demands his money and the buyer dodges payment. Therefore, one must be careful to pay for the Massa in full before Pesach, to avoid any issue of Massa Gezula.
SUMMARY
1. One can fulfill the obligation of Massa with Massa that was carried on Shabbat without an Eruv.
2. One does not have to formally give the Massot to his guest at the Seder.
3. One should pay for his Massa in full at the time of purchase.