We begin our exploration at the Gemara that initiates the fourth Perek of Masechet Berachot, specifically at the top of Kaf-Vav Amud Bet. This section is well-known for discussing the cases where an individual forgets to pray and the subsequent obligation to make up that prayer. The Mishna previously informed us that if someone mistakenly misses Shacharit, they can compensate by praying Mincha Shtayim. If they miss Mincha, they may pray Arvit Shtayim, and if they miss Arvit, they can pray Shacharit Shtayim. This is the law of Tashlumin.
The Gemara introduces a significant Chiddush: one can even make Tashlumin using different forms of the Amida. For instance, if someone forgets to pray Mincha on Friday afternoon, which consists of eighteen or nineteen Brachot, they can pray two Arvit later, despite the latter being a prayer of seven Brachot. The Gemara states: “If one forgot to pray Mincha on Friday, they pray two Arvit on Friday night.” This highlights that even though the two Arvit are for Shabbat, they can still serve as a make-up for the missed Mincha.
In a contrasting case, if one forgets to pray Mincha on Shabbat, they can pray two Arvit on Motzaei Shabbat. Here, they will pray the regular Arvit and then make a Tashlumin, which will also consist of eighteen Brachot. This situation is more complex because it involves the element of Ata Chonantanu, which must be recited during the first Amida. The Gemara concludes that one must recite Ata Chonantanu in the first Amida, as it is the primary prayer of the moment, and does not recite it in the second Amida because that is the make-up for Mincha, which does not require Ata Chonantanu.
If one mistakenly recited Havdala in the second Amida but did not do so in the first, the second Amida counts, while the first does not, as it lacks the necessary Ata Chonantanu. The Gemara questions why missing Ata Chonantanu in the first Amida is treated as if one did not pray at all. It leaves this question unresolved, indicating a significant halachic discussion.
Moving on to the Tosafot, we examine the case where one forgot to mention Rosh Chodesh during Mincha. If someone prays Mincha on Rosh Chodesh but forgets to say Ya'aleh Veyavo, they must repeat the Amida during Arvit. However, Rabbeinu Yehuda argues that they should not pray Arvit Shtayim since they have already fulfilled the requirement of Mincha. The reasoning is that they prayed the Amida and only missed the insertion, which does not warrant another full prayer.
Furthermore, if one mistakenly prays the regular Amida on Shabbat without mentioning Shabbat, they also do not need to pray Arvit Shtayim on Motzaei Shabbat, as they have already fulfilled the requirement of Amida, albeit incorrectly. The Tosafot emphasizes that if there is no gain from repeating the Amida, then one should not do so.
The Tosafot raises a question about whether one can make a Tashlumin for a missed Amida when they were only required to pray seven Brachot but end up praying eighteen. The response indicates that this is permissible as the Gemara maintains that one should pray the full Amida when making up for a missed prayer.
In conclusion, the discussion highlights a fundamental halachic debate regarding whether a prayer that lacks a necessary insertion is considered valid. The Rif and Chachmei Provence argue that such a prayer is null and void, while Rabbeinu Yehuda maintains that it still counts despite the omission. This debate is crucial for understanding the obligations and practices surrounding prayer, particularly in cases of missed Tefillot.