When Sara died in the city of Hevron חֶבְרוֹן, Avraham, her husband, wanted to bury her. Since the Hittites בְּנֵי-חֵת were the landlords, Avraham bought from them the field that had in its corner a cave that later became known as Cave of the Patriarchs מְעָרַת הַמַּכְפֵּלָה Me’arat Ha-mach-pelah (The double cave). There he buried his wife, Sara.
In Pirke De-Rabbi Eliezer we find a legend that shows us why Avraham chose this specific cave to bury Sara, and why this cave turned out to be the cave of the Patriarchs.
“When Avraham made a feast to the angels and wanted to take a tender calf (Genesis 18:7) – the tender calf ran away from him and entered The Double Cave, מְעָרַת הַמַּכְפֵּלָה Me’arat Ha-mach-pelah. Avraham ran after it there, and there he found Adam and Cha’va laying on the beds and sleeping; candles were illuminated above them, and a good scent surrounded them like a sweet savour. Therefore Avraham wanted the cave as a possession of a buryingplace”.
Furthermore, another legend says that Adam and Cha’va are buried in the entrance of the Garden of Eden. Those two legends might explain the source of attraction to the place.
The tradition which starts with Adam and Cha’va continues with three more additional couples; Avraham and Sara, Itzchak and Rivka, Ya’akov and Leah:
A little summary shows that four couples are buried in the cave, and also clarifies why Hebron חֶבְרוֹן is also called Kiryat-Arba קִרְיַת אַרְבַּע (the village of four [couples]) as appeared in Genesis 23:2. “And Sara died in Kiryat-Arba; that is Hevron, in the land of Canaan”.
Regarding the question, why Hevron becomes so important, and is considered to be one of the four holy cities in Israel, we can also learn from its name. The name Hevron חֶבְרוֹן comes from the root ח.ב.ר meaning to connect. That is to say that in the city of Hevron חֶבְרוֹן there is an existing connection with the founding couples of humanity.
Source : Midrash De’Rabbi Eliezer chaper 36