Most likely the unnamed sister who looked after the baby Moses was Miriam (Exodus 2:1-8). She was the eldest of three children who grew up to play a leading part in the establishment of Israel as a new and independent nation (1 Chronicles 6:3; Micah 6:4). She was a prophetess, and led the celebration that followed Israel’s victory over Egypt at the Red Sea (Exodus 15:19-21).
Later, Miriam and Aaron became jealous of Moses because of the supreme power he exercised in Israel (Numbers 12:1-2). Miriam was chiefly to blame, and God punished her with a sudden outbreak of leprosy; but when Moses prayed for her, she was healed. However, just as a daughter who had been publicly rebuked by her father had to spend seven days in shame, so did Miriam. Seven days was also the normal period of isolation for the cleansed leper (Numbers 12:9-15; cf. Leviticus 14:8).
Miriam died in the wilderness between Egypt and Canaan. She was buried at Kadesh-barnea (Numbers 20:1).