The Gemara in Masechet Berachot cites a famous debate regarding the origin of the three daily prayers – Shaharit, Minha and Arbit. Rabbi Yossi held that these prayers were instituted by our patriarchs: Abraham introduced Shaharit, Yishak instituted Minha, and Yaakob established Arbit. Rabbi Yehoshua Ben Levi, by contrast, maintained that the prayers correspond to the ritual offerings in the Bet Ha’mikdash. The Shaharit service corresponds with the morning "Tamid" offering, while Minha parallels the afternoon "Tamid." The sacrificial fats were offered in the Bet Ha’mikdash throughout the night, thus accounting for the Arbit prayer.
The practical difference between these two opinions relates to the status of the Arbit service. If Arbit parallels the offering of fats in the Bet Ha’mikdash, then it cannot be an obligatory prayer, since there were days when all the fats were burned on the altar before the end of the day, and thus nothing was on the altar at nighttime. According to this view, then, the Arbit prayer is an optional service, whereas according to the first view, which maintained that the patriarchs instituted the prayers, there would be no difference between Arbit and the other daily prayers.
The Gemara in Masechet Shabbat (9) discusses this issue as it relates to the question of whether one must interrupt his meal to recite Arbit. If Arbit is mandatory, the Gemara asserts, then certainly one must interrupt what he is doing to recite Arbit when the time for this prayer arrives. If, however, we accept the view that Arbit is an optional prayer, then one is not required to interrupt his meal to recite Arbit; he may recite the prayer afterward. The Gemara comments that in Babylonia, where it was customary to loosen one’s belt as he sat down for a meal, once a person loosened his belt he would not be required to interrupt to recite Arbit. If we accept the view that Arbit is not obligatory, then one who began his meal – which, in Babylonia, means that he loosened his belt – may complete his meal even if just then the time for Arbit sets in.
Abaye raised two questions regarding this Halacha. First, he noted that replacing one’s belt is not a particularly difficult or burdensome task. Why does Halacha allow the person to finish his meal just because he loosened his belt? Why shouldn’t he be required to simply tie it again? Secondly, Abaye asked why the individual cannot pray without a belt. Why does Halacha require him to put on his belt before praying?
The Gemara responds to Abaye’s question by noting that one is indeed required to put on a belt before praying due to the Halacha of "Hikon Likrat Elokecha Yisrael" – "Prepare, O Israel, to greet Your God." This Halacha requires one to prepare his attire so that he looks respectable before he approaches God in prayer. Thus, the Gemara comments, one must, indeed, put on his belt before he begins praying.
Curiously, however, the Gemara does not appear to address Abaye’s first question, namely, that putting on a belt does not entail any difficulty or complex task. What is the answer to this question, and why doesn’t the Gemara offer an answer?
The Ba’al Ha’tanya (Rab Shneur Zalman of Liadi, 1745-1813) answered that the Gemara did, in fact, answer this question, by establishing the obligation to wear a belt for prayer. Once something becomes obligatory, it becomes difficult. The Yeser Ha’ra steps in to dissuade a person from fulfilling his obligations, from completing the tasks assigned to him. True, putting on a belt is not intrinsically a difficult task. But once it is a Halachic obligation, then it becomes a challenge; a person’s evil inclination begins making excuses for why he should not have to do it. The Sages comment that a "Mesuve Ve’ose" – somebody who performs a Misva in which he is commanded – is greater than an "Eno Mesuve Ve’ose" – somebody who performs an optional Misva. For once something becomes an obligation, it is more difficult to do.
Therefore, the Gemara responded appropriately to both questions posed by Abaye. Wearing a belt is indeed obligatory, and for that reason, it is a difficult task, and a person may therefore continue his meal after loosening his belt and recite Arbit afterward.
