Sayyiduna Ibn Abbas (may Allah be pleased with them both) said: Quraysh said to the Prophet (peace and blessings be upon him): Supplicate to your Lord to turn al-Safa into gold for us; if it becomes gold by morning, we will follow you. So he (peace and blessings be upon him) supplicated to his Lord, the Mighty and Majestic, and Jibril (peace be upon him) came and said: Your Lord sends you greetings of peace and says: If you wish, al-Safa will become gold for them by morning, and then whoever of them disbelieves, I will punish him with a punishment with which I have not punished anyone of the worlds; and if you wish, I will open for them the door of repentance and mercy. He (peace and blessings be upon him) said: "Rather, the door of repentance and mercy."
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 12682