Parshat Beshalach is best known for the Az Yashir song that was sung by Bnei Yisrael upon crossing the Yam Suf. ‘On that day, Hashem saved Israel from the hand of Egypt, and Israel saw the Egyptians dead on the seashore. Israel saw the great hand that Hashem inflicted upon Egypt, and the people revered Hashem and they had faith in Hashem and in Moshe His servant’ (Shemot 14:30-31), and it was once they had crossed the sea that Bnei Yisrael began to sing.
However, there is a well-known teaching that appears to challenge the timing of this song. The Gemara states, ‘the angels wanted to say praises (upon the miracle of the Yam Suf), but God said to them, “My creations are drowning and you wish to say praises?”’ (Megillah 10b), which seems to suggest that while Bnei Yisrael had every reason to celebrate, this should not have been done in sight of the drowning Egyptians. So how was it possible for Bnei Yisrael to sing Az Yashir and be praised, while the angels were precluded from singing?
One answer to this question is offered by Rabbi Baruch Halevi Epstein (see Torah Temimah on Shemot 14:20 note 9). He notes that the angels wished to sing praises exactly at that moment when the Egyptians were drowning, and this is why God precluded them from doing so. However, Bnei Yisrael did not sing at that moment, but instead, they waited a little while and only then did they sing. Thus, Az Yashir not only expresses Bnei Yisrael’s faith in G-d, but its timing also points to the sensitivity of Bnei Yisrael towards the Egyptians.
However, a further answer to this question is cited by Rabbi Shimon Schwab (Rabbi Schwab on Prayer p. 238; Ma’ayan Beit Hashoevah p. 164) who explains that while an angel cannot perform two tasks at once (see Bereishit Rabbah 50:2), a human being can. Had the angels begun to sing, their song would have lacked any empathy for the Egyptians and this would have been unacceptable. However, Bnei Yisrael were able to do both. They were capable of expressing their joy about their redemption while also tempering this joy with sensitivity towards the Egyptians who had died. It is this mix of emotions that made the reaction of Bnei Yisrael so great and that made their song so powerful.
Understood this way, Az Yashir is a perfect expression of the Jewish experience, which is that even when we sing, we think about those who are unable to sing, and even when we are joyful, we think about the tragedies in the world (eg. on weddings, we break a glass to remember the loss of the Temple). This is what it means to be human, and this is what it means to be sensitive.