The Prophet warns his kindred of idolatry....

Qabisah ibn al-Mukhariq reported: When the verse was revealed, “Warn your closest kindred,” (26:214) the Prophet, peace and blessings be upon him, set out to the mountain cliffs and ascended to the highest rock. Then, the Prophet called out, “O sons of ‘Abd Manafah! I am warning you! Verily, the parable of myself is that of a man who saw the enemy and set out to guard his people, but he feared they might reach them first, so he shouted: Prepare yourselves!”

Source: Ṣaḥīḥ Muslim 207

Grade: Sahih (authentic) according to Muslim