Mishneh Torah (Rambam) משנה תורה

All blessings begin with "Blessed [are You, God...]" and conclude with "Blessed [are You, God...]," with the exception of the blessing after the recitation of the Shema, blessings that come in succession to each other, the blessings over fruit and the like, the blessings over the fulfillment of the mitzvot, and the blessings that we have mentioned which are expressions of praise and thanks. The [latter blessings] include some that begin with "Blessed [are You, God...]" and do not conclude with "Blessed [are You, God...]" and others that conclude with "Blessed [are You, God...]" but do not begin with "Blessed [are You, God...]." [There are certain exceptions to these rules,] for example, a small number of blessings over the mitzvot, such as the blessing recited [when reading from] a Torah scroll and [some of the blessings recited as an expression of praise and thanks;] for example, the blessing recited when one sees Jewish graves. The rest of the blessings over mitzvot begin with "Blessed [are You, God...]" and do not conclude [with "Blessed are You, God...].

There are positive commandments that a person is obligated to make an effort to pursue [their fulfillment] until he performs them - for example, tefillin, sukkah, lulav, and shofar. These are referred to as obligations, since a person is obligated to fulfill them. There are other mitzvot that are not obligations, but resemble voluntary activities - for example, [the mitzvot of] mezuzah and constructing a guardrail. A person is not obligated to dwell in a house that requires a mezuzah [just in order] to fulfill this mitzvah. Instead, if he desires, he can dwell in a tent or a ship for his entire life. Similarly, he does not have to build a house [just] in order to build a guardrail. A blessing should be recited before fulfilling all positive commandments that are between man and God, whether they are mitzvot that are obligatory or are not obligatory.

Similarly, with regard to all the Rabbinic mitzvot - both the mitzvot that the Rabbis established as obligations - e.g., regarding the megillah, lighting Shabbat candles, and lighting Chanukah candles - and the mitzvot that are not obligations - e.g., an eruv or washing hands - one should recite a blessing before performing them, [praising God] "who has sanctified us with Your commandments and commanded us….” Where has He commanded us [to fulfill these commandments]? In the Torah, which states [Deuteronomy 17:11]: "Act [according to the judgment] they relate to you." [Based on this Biblical verse, the blessing recited before fulfilling a Rabbinical commandment] can be interpreted as follows: Who has sanctified us with Your commandments and commanded us to listen to these [sages] who have commanded us to light Chanukah candles or read the megillah. The same applies regarding all Rabbinic commandments.

Why do we not recite a blessing before washing our hands after [eating]? Because the Sages obligated us [to do] this only because of danger. Blessings are not recited over an [obligation that was instituted] because of danger. To what can this be compared? To someone who strains drinking water at night because of the danger of leeches. [Surely,] he does not recite a blessing, [praising God,] "who commanded us to strain water." The same applies in all similar situations.

[The following rules apply when] a person performs a mitzvah, but does not recite a blessing: If the fulfillment of the mitzvah still continues, he may recite the blessing even though he already performed it. If the mitzvah is a deed that is completed, he should not recite a blessing. What is implied? When a person wrapped himself in tzitzit, donned tefillin, or sat in a sukkah without reciting a blessing at the outset, after wrapping himself [in tzitzit] he should recite the blessing "... who commanded us to wrap ourselves in tzitzit"; after donning [tefillin], he should recite the blessing "... who commanded us to put on tefillin"; after sitting [in the sukkah], he should recite the blessing "... who commanded us to sit in the sukkah." The same applies in all similar situations.

In contrast, if a person slaughtered [an animal] without reciting a blessing, he should not recite the blessing "... who sanctified us with Your commandments and commanded us concerning slaughter," after the slaughter [is completed]. Similarly, if he covered [a fowl's] blood, separated terumah or the tithes, or immersed himself without reciting a blessing beforehand, he should not recite a blessing afterwards. The same applies in all similar situations.

There is no mitzvah for which the blessing should be recited after its fulfillment, with the exception of the immersion of a convert. [In this instance, the exception was made] because he could not say, "who sanctified us with Your commandments and commanded us." Until [the convert] immersed himself, he was neither sanctified nor commanded. Therefore, he recites the blessing over the immersion [only] after immersing himself. [This is allowed] since at the outset, he was unfit and unable to recite the blessing.

Whenever the performance of a mitzvah constitutes the completion of one's obligation, he should recite the blessing before performing it. When, however, there is another commandment that follows the performance of a particular mitzvah, the blessing should not be recited until the other mitzvah is performed. What is implied? When a person makes a sukkah, a lulav, a shofar, tzitzit, tefillin, or a mezuzah, he should not recite a blessing at the time he made [them]: [praising God for] "sanctifying us with Your commandments and commanding us to make a sukkah" or "a lulav," or "to write tefillin," because there is another commandment that follows this action. When is the blessing recited? When one sits in the sukkah, shakes the lulav, hears the sounding of the shofar, wraps oneself in tzitzit, dons tefillin, or affixes the mezuzah. In contrast, when one constructs a guardrail, before constructing it one should recite the blessing "...who has sanctified us with Your commandments and commanded us to construct a guardrail." The same applies in all similar situations.

The blessing shehecheyanu is recited: [before] fulfilling every mitzvah that we are obligated to fulfill only at a specific time - e.g., shofar, sukkah, lulav, reading the Megillah, and [lighting] Chanukah candles, [before fulfilling] every mitzvah that involves the acquisition of property - e.g., tzitzit, tefillin, and a guardrail - and [before fulfilling] every mitzvah that we are obligated to fulfill infrequently - for this resembles a mitzvah we are obligated to fulfill only at a specific time - e.g., circumcising one's son and redeeming him. If one did not recite the blessing shehecheyanu when making a sukkah or a lulav, one should recite this blessing when fulfilling the mitzvah. The same applies in other similar situations.

Whether a person performs a mitzvah for himself or for a colleague, before performing the mitzvah, he should recite the blessing "... who has sanctified us with Your commandments and commanded us...." He should, however, recite the blessing shehecheyanu only on mitzvot that he is performing for himself. If a person is [intending to] fulfill several mitzvot, he should not recite the blessing "... who has sanctified us with Your commandments and commanded us to fulfill the mitzvot ---." Instead, he should recite a blessing over each mitzvah individually.

Whoever performs a mitzvah for his own sake, whether it is an obligation incumbent upon him or not, should recite a blessing, [praising God "who sanctified us with Your commandments and commanded us] to perform ----." In contrast, if he performs a mitzvah on behalf of another person, the form of the blessing is ["who sanctified us... and commanded us] concerning the performance of ----."

What is implied? Before donning tefillin, one recites the blessing "... to put on tefillin"; before wrapping oneself in tzitzit, one recites the blessing "... to wrap..."; before sitting in the sukkah, one recites the blessing "...to sit in the sukkah." Similarly, one recites the blessings "... to kindle the Sabbath light," and "... to complete the Hallel." Similarly, if one affixes a mezuzah on one's own house, one should recite the blessing "... to affix a mezuzah"; if one erects a guardrail on one's roof, one should recite the blessing "... to erect a guardrail." Should one separate terumah for oneself, one should recite the blessing "... to separate [terumah]." Should one circumcise one's own son, one should recite the blessing "... to circumcise [one's] son." Should one slaughter one's Paschal sacrifice or festive sacrifice, one recites the blessing "... to slaughter...."

If, however, one affixes a mezuzah for others, one should recite the blessing "... concerning the affixing of a mezuzah." Should one construct a guardrail for others, one should recite the blessing "... concerning the building of a guardrail." Should one separate terumah for others, one should recite the blessing "... concerning the separation of terumah. Should one circumcise a colleague's son, one should recite the blessing "... concerning the circumcision." The same applies in all similar situations.

[The following rules apply] when a person performs a mitzvah on his own behalf and on behalf of others simultaneously. If the mitzvah is not obligatory in nature, he should use the form "... concerning..." for the blessing. Therefore, one recites the blessing "... concerning the mitzvah of eruv." If the mitzvah is obligatory and he had the intent of fulfilling his own obligation and that of the others, he should use the form "... to..." for the blessing. Therefore, one recites the blessing "... to hear the sound of the shofar."

When one takes the lulav, one should recite the blessing "... concerning the taking of the lulav." [This form is used] because a person fulfills his obligation when he picks [the lulav] up. If one recites the blessing before taking the lulav, one should recite the blessing "... to take the lulav," as one recites the blessing "... to sit in the sukkah." From this, one derives the principle that a person who recites a blessing after performing [a mitzvah] blesses "... concerning..." [the mitzvah's] performance. With regard to the washing of hands and ritual slaughter, since they are of a voluntary nature, even if a person slaughters on his own behalf, he should recite the blessings "... concerning slaughter," "... concerning the covering of the blood," and "... concerning the washing of hands." Similarly, one recites the blessing "... concerning the destruction of chametz," whether one searches for leaven on one's own behalf or on behalf of others. [This form is used] because once a person resolves in his heart to nullify his ownership [over chametz], the mitzvah of destroying it is fulfilled even before one searches, as will be explained in its place.

[A blessing is not recited over] all practices that are customs. [This applies] even to a custom established by the prophets - for example, taking the willow branches on the seventh day of Sukkot. Needless to say, a blessing is not recited over customs established by the Sages - e.g., reading Hallel on Rosh Chodesh and on the intermediate days of Pesach. Similarly whenever there is a question whether a practice requires a blessing or not, it should be performed without reciting a blessing. A person should always take care not to recite blessings that are not necessary, and should recite many blessings that are required. Thus, David declared [Psalms 145:2]: "I will bless you each day."