Parshat Haazinu is the Parsha most commonly read on Shabbat Shuva, but what does the Parsha have to do with Teshuva? In the Parsha is the Shira, in which Moshe tells Bnei Yisrael that they will do Aveirot and they will get punished. If this is the case, why is it called a Shira? The Lubavitcher Rebbe explains that the answers to these questions can be found in a Midrash that discusses a conversation between Moshe and Hashem based on Pesukim from Tehillim. Moshe tells Hashem, “Lo Amut Ki Echyeh Vaasaper Maaseh Kah,” “I should not die so that I can tell the world the wonders of Hashem.” Hashem shows Moshe his portion in Olam Haba, and Moshe says "Pitchu Li Shaarei Tzedeek,” “open up the gates of righteousness.” Moshe is saying that he wants to die so that he can enter Olam Haba. The Midrash does not seem to make sense! Upon seeing his portion in Olam Haba, Moshe Rabbeinu, who dedicated his whole life to Bnei Yisrael, says “forget Bnei Yisrael”? The Lubavitcher Rebbe answers that Hashem showed Moshe that even though Bnei Yisrael sinned, they will do Teshuva and they will be forgiven. Therefore, Moshe said, “If that is the case, then I can die.” From this, we can understand why Haazinu is called a Shira and why it is read on Shabbat Shuva. The reason is that Haazinu describes how in the future we will sin, but we have to understand that we still can do Teshuva and be redeemed and bring Mashiach.