The Talmud tells us that it is forbidden for people to fill their mouths with laughter in this world (B. Brachot 31a). The source for this rule is the verse: "Then will our mouth be filled with laughter and our tongue with joyous song" (Psalms 126:2). "Then" we can joyously laugh and sing, but not now. When is "then"? The biblical verse continues: "They will declare among the nations - God has done greatly with these," that is, with the Jewish people. Only when there is universal acknowledgment of the Almighty's role in reestablishing the Jewish people in our national homeland can we rejoice. Thus the Talmud lauds one of the sages who religiously followed this dictum, never filling his mouth with laughter after hearing this instruction, and indeed this prohibition is recorded in the codes (Shulhan Aruch OH 560:5). The commentators discuss the reason for this prohibition offering a number of approaches. One approach suggests that this limitation is in deference to our exilic existence; as long as the Temple is not standing, we are effectively mourners and it is inappropriate to laugh heartily. Thus the proscription against laughing will be rescinded when the Temple is rebuilt and the mourning period a matter of the past (Meiri, 13th century, Provence). An alternative approach notes that there is no reference in the talmudic passage to the Temple - neither its destruction nor its reconstruction. Thus the prohibition against excessive laughing appears not to be connected to mourning over the ruin of our Temple. Rather, unbridled frivolity is a perilous formula for neglecting the mitzvot and hence proscribed. According to this approach, why will laughter be one day permitted? Despite its dangers, unchecked joy will be permitted as a publicized acknowledgment of the divine miracles bestowed upon us. When the nations of the world see our elation, they will indeed salute the Almighty. Our joy, therefore, will serve the purpose of advertising the Almighty's wonders (Rabbeinu Yona Gerondi, 13th century, Spain). A third position combines the previous two positions: Joy unconnected to mitzvot is too dangerous to ever be permitted. Hearty joy over the fulfillment of mitzvot, on the other hand, was permitted as long as the Temple stood. Since its destruction, however, there is no license even for this type of joy (Taz, 17th century, Poland). Does this rule necessitate a morose demeanor in our day? Should our homes, our streets, our workplaces be filled with sullen looks? From other talmudic passages in our tractate it would appear not (B. Brachot 9b). When one of the Babylonian sages was preparing to journey to the Land of Israel, a colleague approached him: "When you ascend there - referring to the Land of Israel - inquire after the well-being of my brother Rav Bruna." Seeking to accord honor to Rav Bruna, he continued: "Inquire in the presence of the entire group for my brother is a great man and rejoices in the performance of mitzvot." The colleague continued, telling of his brother's greatness: "Once, he joined the redemption blessing said in the morning prayer to the silent Amida prayer at sunrise, and the smile at his achievement did not leave his lips the entire day." Thus a seemingly minor accomplishment in prayer led Rav Bruna to walk around smiling for the entire day and for this he was lauded as a great person. It is unclear whether Rav Bruna was a great person and rejoiced as he discharged his obligations, or perhaps he was a great person because he rejoiced in the fulfillment of mitzvot. Either way, we see that while Rav Bruna may not have filled his mouth with laughter, he certainly did not walk around with a dour countenance. In another talmudic passage we hear of palpable joy being expressed with regard to the study of Torah (B. Menahot 18a). Rabbi Yehuda the Prince, commonly known as simply Rebbi, reported that he once traveled to Rabbi Elazar ben Shamua to exhaustively extract the knowledge of this sage. When he arrived he found Yosef the Babylonian sitting before Rabbi Elazar ben Shamua. This student was the most beloved student of Rabbi Elazar ben Shamua, and he sat before his teacher probing finer points of ritual Temple law. As Rabbi Elazar ben Shamua answered his prize student's queries, Yosef the Babylonian's face noticeably lit up. Seeing the change in his disciples demeanor, Rabbi Elazar ben Shamua commented: "It appears to me that up to this point our teachings were inaccurate, for you only reacted positively now. Does this mean that until now you consider everything said to be incorrect?" Yosef the Babylonian replied: "Indeed all the teachings have been appropriate, but this law has particular meaning for me. I remembered a rabbinic teaching from another teacher that no one else seemed to recollect. I went around to all my fellow students searching for a companion who recalled the teaching. Alas to no avail. I was concerned lest my memory was faulty. The law that you have just taught is exactly that teaching, and I feel like you have just returned a lost article to me!" Thus Yosef the Babylonian explained his sudden shiny countenance. Rabbi Elazar ben Shamua was moved by his faithful student's story and with joyful tears streaming down his face he declared: "Fortunate are you, O wise students of Torah, that the words of Torah are so intensely beloved to you." The teacher added a biblical verse which he felt aptly described his dearest pupil: "How I love your Torah; all the day it is my conversation" (Psalms 119:97). Thus we have two paradigms of openly displayed delight - Rav Bruna's elation at his prayer achievement and Yosef the Babylonian's joy at hearing a long-lost Torah lesson. We are enjoined to remember our unredeemed state by tempering our laughter; we are warned that unbridled joyfulness may lead to reckless sin. Nevertheless, we need not walk around with glum expressions. True bliss at our spiritual achievements need not be hidden behind sullen demeanors; we are allowed to walk around with a smile. The writer is on the faculty of Pardes Institute of Jewish Studies and is a rabbi in Tzur Hadassah.