Rosh Hashanah 29 - Rosh Hashanah on Shabbat
Even though we saw Rava earlier postulate that one can simply play music on a shofar and fulfill his Rosh Hashanah shofar obligation without meaning to do so, in truth the intention is paramount. Here is an example. " When Moses would raise his hand, Israel would prevail over Amalek, but when he lowered his hand, Amalek was stronger ." But do Moses' hands make or break the battle? Rather, when Israel, "gazed upward," concentrating on the purpose of the battle, they would win. Thus, Moses's hands was only a signal to Israel. Others explain that the concentration of Israel was giving Moses the strength to pray. Another example: " Make a fiery serpent and place it on a pole, so that anyone bitten by a snake would look at the serpent and live ." (numbers 21:8) Rather, when Israel "gazed upwards," they were healed.
Even when Rosh Hashanah occurs on Shabbat, by right people should blow the shofar nevertheless. However, since there is a danger that someone who is not skilled in the shofar will take it in his hand and go to a Sage in order to learn - and carrying objects in a public area is prohibited on Shabbat - the Sages decided to cancel blowing the shofar in this case. In Jerusalem in the times of the Temple, when the presence of many Sages would ensure that Shabbat is observed, they would blow the shofar even on Shabbat.
After the destruction of the Temple, Rabbi Yochanan ben Zakkai established to still blow the shofar on Shabbat Rosh Hashanah in the city of Yavneh, where the Sanhedrin assembled. Here is how he did it. They told him, "Let's decide first if it is proper." He answered, "Let's blow now, and afterward decide." So they blew the shofar. Then later, when they said, "Let's decide now," Rabbi Yochanan answered, "It is too late - the sound was already heard, and it is improper for the Court to retract its decision at this time."
Art: View Of Jerusalem by Pierre Tetar Van Elven