solid food, and Revi'it for a liquid) is consumed within a predefined time period (different for solids and liquids). When performing a mitzvah Blessings recited before the observance of a mitzvah (commandment) begin with the formula "Blessed are You, Lord our God, King of the Universe, who has sanctified us through his commandments and commanded us to..." and mention the specific mitzvah about to be performed. The blessing over fulfilling the commandment is sometimes followed by another blessing (for example, when lighting the Chanukkah candles, the additional berakhah "...who performed miracles for our ancestors long ago at this season" is recited). When a mitzvah is performed for the first time in the year, the She'hecheyanu blessing ("...who has kept us alive and preserved us and enabled us to reach this season") is also added. Contrary to the usual pattern of making a blessing before the commandment, the blessing for relieving one's bodily needs and the blessing for ritually rinsing the hands are both recited afterwards. In the former case, it is forbidden to recite any blessing while one feels one's need, and so the blessing is postponed. In the latter case, one may also not recite the blessing beforehand since clean hands are a prerequisite for reciting the blessing. Even if one is certain that one's hands are clean (for example, at the Rabbinically-instituted rinsing before breaking bread), one still recites the blessing afterwards to avoid confusion. Also contrary to the usual pattern, blessings are said after certain public readings from the Tanakh as well as before it. Examples include the public reading of the Torah, the readings from the prophets called the Haftarah, and the recitation of Psalms of Praise, and the Psalms of the Hallel. Mitzvot for which a blessing is not recited No blessing is recited for the performance of certain commandments. Some commentators have suggested that the reason is that no blessing is said before fulfilling commandments which do not involve any action (for example, leaving the corner of the field for the poor), or the observance of which is possible only in undesirable circumstances (for example, granting a divorce, or the return of stolen goods). In the case of other commandments (for example, giving charity), commentators say it is because there is no fixed amount or limit to the observance of the commandment; however, there is no general agreement regarding the underlying principles. Abudirham wrote