רבינו בחיי — אז ישיר

Q — Why is the song at the Sea called שירה (feminine) while the final redemption's song will be called שיר (masculine)?

A — Rabbeinu Bachya catches the grammatical shift and makes it cosmological. A שירה is feminine because it carries within itself the possibility of being followed by something else, the way a woman conceives, gives birth, and conceives again — and so this שירה at the Yam gave birth to another galut (Bavel), which gave birth to another (Yavan), and on through history. Every song of redemption in feminine form is provisional; it leaves room for a sequel. The future song — "שירו לה' שיר חדש" and "ביום ההוא יושר השיר הזה" — is masculine because it is final; nothing follows it. Israel sings שירה in the present tense of history, and one day will sing שיר when history closes.