What is the significance of two women?
Rashi: They are two countries, that are like two women.
Malbim: They are Malchus Efrayim and Yehudah. Hashem's relation to Yisrael is like a man to his wife. He made a Bris of lovers with them. When they veer from under Him to serve foreign service (idolatry), they are depicted as a wife who is Mezanah under her husband.
What is the significance of having the same mother?
Rashi: Both are from one Kenesiyah; they were divided into two in the days of Rechav'am.
Radak: The united Kenesiyah is depicted as a mother, and when it is divides, they are like daughters.
Malbim: Even though now Efrayim and Yehudah are divided, initially they were always one nation.
