وَعَنْ ثَوْبَانَ مَوْلَى رَسُولِ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَآلِهِ وَسَلَّمَ رَضِيَ اللَّهُ عَنْهُ قَالَ قَالَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَآلِهِ وَسَلَّمَ ”إِذَا رَأَيْتُمُ الرَّايَاتِ السُّودَ قَدْ جَاءَتْ مِنْ قِبَلِ خُرَاسَانَ فَأْتُوهَا فَإِنَّ فِيهَا خَلِيفَةَ اللَّهِ الْمَهْدِيَّ“
Mawla of the Messenger, Sayyiduna Thawban (may Allah be pleased with him) narrates that the Messenger of Allah (peace and blessings be upon him and his family) said: When you see black flags coming from the direction of Khurasan, then go towards them and join them, for among them will be Allah’s Caliph, Mahdi.