“Then Miriam the prophetess, Aaron’s sister, took a timbrel in her hand, and all the women went out after her in dance with timbrels”
Exodus 15:20
This is clearly Miriam’s moment! It is the first time in the Torah Miriam is referred to as “a prophetess” and named in her own right, not as adjunct to her family members.
Her song of praise that accompanies the dance begins confidently and assertively with the triumphal “Sing to God!” Although her song is shorter than Moses’s, its energy and confidence is uplifting. Whereas Moses begins with a slight hesitation, “So, they sang to God”, Miriam’s outstanding characteristic here is her sureness: “Sing to the Lord, for He has triumphed gloriously; horse and driver He has hurled into the sea.”
Rashi extends her lack of doubt in the successful outcome of the Exodus to the Israelite women in general: “the righteous women of that generation were confident that God would do miracles for them; so they brought drums with them from Egypt”.