Sayyiduna Ibn Abbas (may Allah be pleased with them both) said concerning "And We have not sent you except as a mercy to the worlds" [Surah al-Anbiya: 107]: "Whoever follows him (peace and blessings be upon him), for him there is mercy in this world and the Hereafter; and whoever does not follow him is kept safe from the punishment that befell other nations, namely being transformed, being swallowed by the earth, and being pelted with stones."
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 12306