Musar על נדרים 55:15

Our sages in Eruvin 53a have said that the reason the cave Abraham and Sarah were buried in is called מערת המכפלה, is from the word כפול, twin, or double, an appropriate name for a grave containing husbands and their wives, i.e. זוגות. What advantage is there in the fact that this cave houses the remains of husband and wife respectively? The meaning of our sages is that these pairs are all united with one another, that they are not separate pairs. Once the last of the four pairs, i.e. Jacob came to burial whose מטתו שלמה, whose "bed" was complete (since Leah had born him six sons and one daughter whose name was דינה),this symbolized the six days of creation and the Sabbath.

Leah, who was anchored in the emanation בינה, the 7th counting from מלכות, bore 7 children, 6 sons and a daughter. The emanation בינה radiates creative activity in 6 directions as we have demonstrated earlier. The single daughter represents the emanation מלכות [we have explained that relationship also], her name was דינה, and our sages have stated that this represents the halachic principle of דינא דמלכות דינא, "that decrees issued by the government are legally binding on us." The letters in that word are a rearrangement of the letters in the name א-דני, one of G–d's names.