Ruling on a topic debated in the Talmud (Berakhot 21a), the Rambam (Hilkhot K’riat Shma 2:3) rules that one who is unsure whether or not he recited k’riat shma must then recite it, as it is a biblical obligation and thus requires stringency. In formulating this rule, he requires the birkhot k’riat shma to be recited as well.

Normally, berakhot, as rabbinic commandments, are omitted when it is unclear that they are necessary. However, when a biblical mitzvah itself is performed out of uncertainty (safek), the issue of reciting a berakhah on that mitzvah is a topic of debate in rishonim. Rabbeinu Yonah feels that such a berakhah is recited, and his opinion is brought in at least three places: in this context in Berakhot 21b, regarding k’riat shma; cited by the Rosh (Chulin 83b) regarding covering the blood following the shechitah of an animal that is unclear as to its obligation in this mitzvah (the Rosh disagrees); cited by the Ran (Shabbat 135a) regarding a milah that may be unnecessary (the Rif disagrees).

While Rabbeinu Yonah is thus consistent, the Rambam is more difficult. Outside of k’riat shma, his position seems to be that one does not recite a berakhah when the obligation is uncertain (see Resp. Rashba, 320; and Mishneh Torah, Hil. Tzitzit 3:9; Hilkhot Milah 3:6; Hilkhot Shechitah 14:14; Hilkhot Sukkah 6:13).

Some acharonim (see R. Shlomo Wahrman’s Sh’erit Yosef, I, 1) explain that the issue here is the status of birkhot k’riat shma. While some rishonim saw these berakhot as berakhot on the mitzvah of k’riat shma, comparable to all other birkhot hamitzvot (see Ritva, Rosh HaShanah 34a; Ramban Berakhot 22b; and Rosh, Berakhot 1:1 citing R. Amram Gaon), the Rambam’s position seems to be that they are not birkhot hamitzvot. Rather, they are prayers instituted as part of the process of k’riat shma (see Hilkhot K’riat Shma, 1:7, with Kessef Mishneh.) Thus, as they are part of the k’riat shma obligation, the Rambam requires them to be recited even when the obligation to say k’riat shma is itself not definite. In all other cases, when the berakhot involved are purely birkhot hamitzvot, he rules those berakhot should be omitted.