Sayyidah al-Shamus bint al-Nu'man (may Allah be pleased with her) said: When the Messenger of Allah (peace and blessings be upon him) arrived, halted and laid the foundation of this mosque, that is, the Quba Mosque, I was watching him. I saw that he would carry a stone or a rock until the stone (its weight) bent him over, and I would see the whiteness of the dust on his stomach and navel. A man from among his Companions would come and say: "May my father and mother be ransomed for you, O Messenger of Allah! Give it to me, let me take it off your hands." But he (peace and blessings be upon him) would say: "No, take another stone like it," until he had completed the foundation. And he would say: "It is Jibril (peace be upon him) who is guiding toward the Ka'bah." So it used to be said that it is the most accurate of mosques in the direction of its qiblah.
Hadith Referenceالمعجم الكبير للطبراني / مسند النساء / 21172