Narrated Abu Masud:The Prophet (ﷺ) beckoned with his hand towards Yemen and said, "Belief is there." The harshness and mercilessness are the qualities of those farmers etc, who are busy with their camels and pay no attention to the religion (is towards the east) from where the side of the head of Satan will appear; those are the tribes of Rabi`a and Mudar.
حَدَّثَنِي عَبْدُ اللَّهِ بْنُ مُحَمَّدٍ الْجُعْفِيُّ، حَدَّثَنَا وَهْبُ بْنُ جَرِيرٍ، حَدَّثَنَا شُعْبَةُ، عَنْ إِسْمَاعِيلَ بْنِ أَبِي خَالِدٍ، عَنْ قَيْسِ بْنِ أَبِي حَازِمٍ، عَنْ أَبِي مَسْعُودٍ، أَنَّ النَّبِيَّ صلى الله عليه وسلم قَالَ " الإِيمَانُ هَا هُنَا ". وَأَشَارَ بِيَدِهِ إِلَى الْيَمَنِ " وَالْجَفَاءُ وَغِلَظُ الْقُلُوبِ فِي الْفَدَّادِينَ، عِنْدَ أُصُولِ أَذْنَابِ الإِبِلِ مِنْ حَيْثُ يَطْلُعُ قَرْنَا الشَّيْطَانِ رَبِيعَةَ وَمُضَرَ ".
Bukhari
Military Expeditions led by the Prophet (pbuh) (Al-Maghaazi) • Hadith 410