One of the most famous reasons given for the Misva of Shofar is that it serves to invoke the merit of Akedat Yitzhak, when Abraham Abinu was prepared to obey God’s command to offer his beloved son, Yitzhak, as a sacrifice. At the last moment, God told Abraham to withdraw his knife, and Abraham offered in Yitzhak’s place a ram that he saw nearby and which was caught by its horns in the bushes. We blow a ram’s horn on Rosh Hashanah, when we stand in judgment before God, in order to bring to mind the merit of the Akeda, as this will help ensure a favorable and merciful judgment.
This association between the Misva of Shofar and Akedat Yitzhak may explain an otherwise perplexing custom that is observed in many communities. It is customary for the Toke’a (person who blows the Shofar in the synagogue) to cover the Shofar just before the Shofar blowing, as he recites the Berachot of "Li’shmo’a Kol Shofar" and "Shehehiyanu." He places the Shofar underneath his kouracha (Tallit bag), and leaves it covered until after he recites the Berachot, when he is ready to begin blowing. This custom is mentioned by the Elya Rabba (Rav Eliyahu Shapiro of Prague, 1660-1712), who explains that this practice commemorates the incident of Akedat Yitzhak. As Abraham constructed the altar upon which to offer his son, he feared that the Satan, in its effort to disrupt the sacrifice, may throw a rock at Yitzhak in order to inflict a wound, which would render Yitzhak blemished and hence unfit as an offering. Abraham therefore covered Yitzhak to hide him from the Satan. We commemorate Abraham’s devotion by covering the Shofar just before it is blown.
Others suggest a different reason for covering the Shofar. It once happened in a certain community that the Toke’a was incapable of producing a proper sound from the Shofar. Despite his struggles, he could not produce a proper Shofar sound. The Rabbi determined that the Satan, knowing the immense value of the Shofar blowing in arousing divine mercy upon the Jewish people, possessed the Shofar so that the congregation would be incapable of performing this invaluable Misva. The solution, as is recorded in a number of books, is to whisper to the Shofar the verse, "Vi’hi No’am Hashem Elokenu Alenu U’ma’aseh Yadenu Konena Alenu…" (Tehillim 90:17). The Rabbi whispered this verse, and the Toke’a was able to blow the Shofar properly.
It thus emerges that the Shofar is vulnerable to the Satan’s machinations, and the Satan is capable of possessing the Shofar to prevent us from performing the Misva. Accordingly, some explain that we cover the Shofar in order to protect it from the Satan’s determined efforts to sabotage the Misva.
The Ben Ish Hai (Rav Yosef Haim of Baghdad, 1833-1909) ruled that even though the Shofar is covered during the recitation of the Berachot, the Toke’a must hold it during this period. As he recites the Berachot, his right hand must be underneath the kouracha, holding onto the Shofar. Upon completing the Berachot, he lifts the Shofar over the kouracha to begin the blowing.
Summary: It is customary for the Toke’a to keep the Shofar covered underneath the Tallit bag as he recites the Berachot of "Li’shmo’a Kol Shofar" and "Shehehiyanu." He should hold the Shofar with his right hand underneath the Tallit bag as he recites the Berachot.
