It is narrated from Sayyiduna Ibn Abbas (may Allah be pleased with them both) that the Prophet (peace and blessings be upon him) preferred the gate of repentance and mercy over al-Safa turning into gold. This is a sahih and preserved (mahfuz) hadith from the narration of al-Thawri from Salamah bin Kuhayl. Imran bin al-Hakam al-Sulami is one of the senior Tabi'in who is used as evidence. The two of them (Bukhari and Muslim) left this hadith out only - and Allah knows best - because of a discrepancy in its chain from Yahya bin Salamah bin Kuhayl, and Yahya makes many errors in narrating from his father.