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 Rabiʿa and Mudar. (Using translation from Bukhārī 4387)
أَنَّ النَّبِيَّ ﷺ قَالَ «الْإِيمَانُ هَاهُنَا وَأَشَارَ بِيَدِهِ إِلَى الْيَمَنِ وَالجَفَاءُ وَغِلَظُ الْقُلُوبِ فِي الْفَدَّادِينَ عِنْدَ أُصُولِ أَذْنَابِ الْإِبِلِ حَيْثُ يَطْلُعُ قَرْنُ الشَّيْطَانِ فِي رَبِيعَةَ وَمُضَرَ»