^ 16.The Rishonim disagree about whether or not mitzvot require kavana. SA 60:4, 690:13-14 rules that in practice, mitzvot indeed require kavana. Many Aĥaronim maintain that this applies to rabbinic mitzvot as well, meaning that one does not discharge his obligation if he does not intend to fulfill the mitzva. Le-khatĥila, one should express this kavana clearly in one’s mind. However, even if one does not have explicit kavana, he is still viewed as having kavana if he would answer the question, "Why did you read the Megilla?" by saying, "To fulfill the mitzva" (MB 60:10). Therefore, one who comes to the synagogue for Megilla reading or recites a berakha before reading the Megilla clearly has kavana and discharges his obligation. Only one who stays at home and overhears the reading from the synagogue does not discharge his obligation unless he explicitly intends to fulfill the mitzva.
^ 17.In contrast to the berakhot we recite before the reading, "Ha-rav et riveinu" is not obligatory. Rather, it is a berakha of praise and thanksgiving that depends on one’s custom, as the Mishna states, "In a place where it is customary to recite the berakha, one should recite it, and in a place where it is customary not to recite the berakha, one should not recite it" (Megilla 21a). Nowadays, everyone recites it. Orĥot Ĥayim quotes the Yerushalmi as saying that one recites it only in a minyan, and Beit Yosef and Rema 692:1 codify this. However, Rashi, Maharam, and Radbaz maintain that even an individual recites it. Ben Ish Ĥai, Year 1, Hilkhot Purim 13 (Tetzaveh) concurs, and those who follow the rulings of Ben Ish Ĥai act accordingly. BHL 692:2 and Yabi’a Omer, OĤ 8:56 state that one should not recite the berakha unless a minyan is present, because it is a case of uncertainty. (This decision is especially logical in light of the ruling of Behag and Mahari Weil that an individual omits even the first three berakhot.) The prevalent custom is not to recite it when reading the Megilla alone, but one should not rebuke those who want to recite it. It is uncertain whether women count toward the ten (Rema 690:18). Pri Ĥadash and Pri Megadim state that this uncertainty relates only to the question of whether women can be counted together with men, but a minyan of ten women certainly recites the berakha. Although some have a custom not to recite it, the halakha follows those who maintain that it should be recited in the presence of ten women, as Mikra’ei Kodesh (Frank), Purim 35 and Yabi’a Omer, OĤ 8:56:4 state. It seems that, in practice, women can also be counted together with men, be-di’avad, since many authorities maintain that even one person may recite this berakha.