"A Miriam’s Cup is a new ritual object that is placed on the seder table beside the Cup of Elijah. Miriam’s Cup is filled with water. It serves as a symbol of Miriam’s Well, which was the source of water for the Israelites in the desert. Putting a Miriam’s Cup on your table is a way of making your seder more inclusive.
It is also a way of drawing attention to the importance of Miriam and the other women of the Exodus story, women who have sometimes been overlooked but about whom our tradition says, "If it wasn’t for the righteousness of women of that generation we would not have been redeemed from Egypt" (Babylonian Talmud, Sotah 9b).
There are many legends about Miriam’s Well. It is said to have been a magical source of water that followed the Israelites for 40 years because of the merit of Miriam. The waters of this well were said to be healing and sustaining. Thus Miriam’s Cup is a symbol of all that sustains us through our own journeys, while Elijah’s Cup is a symbol of a future Messianic time."