Sayyiduna Safeena (Radhiallaahu Anhu) reports that Rasulullah (Sallallaahu Alayhi Wasallam) said, ‘The Khilaafat will last for 30 years, thereafter Allah will grant kingdom to whomsoever He wishes.’ (Sunan Abi Dawud Hadith4614; Sunan al-Tirmidhi; Sahih ibn Hibbaan vol.15 pg.35)