Sayyiduna Ibn Abbas (may Allah be pleased with them both) said: When this verse was revealed: "And warn your nearest kinsfolk" [Surah al-Shu'ara: 214], the Prophet (peace and blessings be upon him) climbed Mount al-Safa and called out: "Wa sabahah!" (the customary cry warning of danger).
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 12300