Rabbi Lapin says
“Years of slavery in Egypt damaged Jewish family life. For its very first ritual as a nation, God gathered the Israelites, not into political, tribal, gender, or labor groupings but into individual families. By asserting the bond between husband, wife and children, God was reestablishing the importance of the family as societys fundamental element. Hence, rule number one.”
God was reestablishing the importance of the family as societys fundamental element. Hence, rule number one.
That is where the 12 tribes got started, and before that the Arabs started becoming a nation because of the polygamy of our ancestors.