Rabbi Berekhya began: “Sound the shofar at the New Moon [at the covering of our festive day]” (Psalms 81:4). Are all the months not the New Moon?12How is it clear from the verse that the mitzva to sound the shofar is specific to Rosh HaSshana? “At the covering,”13The moon is not visible at the beginning of every month. – is [the moon] not covered [at the beginning] of all months? Rather, “of our festive day.”
But is Nisan also not a month that is covered and has its own festival? Rather, which is the month that is covered, has a festival, and its festival is on that day? You find it only in the month of Tishrei. In this month, renew your actions.14The phrase “at the New Moon [baḥodesh]” is expounded to mean renew [teḥadeshu] your actions, meaning reexamine and improve your ways.
“The shofar” – in this month, improve [shaperu] your actions. The Holy One blessed be He said to Israel: ‘If you have improved your actions, I will become like this shofar for you. Just as this shofar takes in from this side and lets out from that side, so I rise from My throne of justice and sit on My throne of mercy and transform the attribute of justice to the attribute of mercy.’ When? In the seventh month.