"Miriam... took a tambourine in her hand; and all the women went out after her with timbrels and with dances..." (Song at the Sea, Exodus 15:20) How did the Israelites have tambourines in the desert? But the righteous women of that generation were certain that G-d will perform miracles for them, and they prepared tambourines and dances while still in Egypt...
Midrash Mechiilta; Rashi on verse
