These three sites are the very ones by which Allah swore in the Quran when He said:

“By the fig and the olive, by Mount Sinai, and by this secure city! We have certainly created man in the finest mould, then We returned him to the lowest of the low—except for those who believe and do righteous deeds; for them there is an unfailing reward. So what can still make you deny the Judgment? Is not Allah the wisest of judges?” (95:1–8).

He swore by “the fig and the olive,” meaning the Holy Land where these trees grow, the land from which the Messiah was sent and upon which the Gospel was revealed to him. He swore by “Mount Sinai,” the mountain on which Allah spoke to Moses, calling to him from the right side of the valley, from the blessed spot, from the tree. And He swore by “this secure city,” that is, Mecca—the town in which Abraham settled his son Ishmael and Ishmael’s mother; the very town that Allah made a sacred, inviolable sanctuary, safe and secure, while people all around were being snatched away, both by the laws of creation and by divine command, by decree as well as by legislation.

It was Abraham who declared it sacred and prayed for its people, saying: “Our Lord, I have settled some of my descendants in a valley without cultivation, near Your Sacred House, our Lord, so that they may establish the prayer. So incline some hearts among mankind toward them, and provide them with fruits, that they may give thanks.” (14:37).