Sahih al-Bukhari 3592
Sahih al-Bukhari · Book 61: Virtues and Merits of the Prophet (pbuh) and his Companions · The signs of Prophethood in Islam
Narrated `Umar bin Taghlib:
حَدَّثَنَا سُلَيْمَانُ بْنُ حَرْبٍ ، حَدَّثَنَا جَرِيرُ بْنُ حَازِمٍ ، سَمِعْتُ الْحَسَنَ ، يَقُولُ حَدَّثَنَا عَمْرُو بْنُ تَغْلِبَ ، قَالَ سَمِعْتُ رَسُولَ اللَّهِ صلى الله عليه وسلم يَقُولُ " بَيْنَ يَدَىِ السَّاعَةِ تُقَاتِلُونَ قَوْمًا يَنْتَعِلُونَ الشَّعَرَ، وَتُقَاتِلُونَ قَوْمًا كَأَنَّ وُجُوهَهُمُ الْمَجَانُّ الْمُطْرَقَةُ " .
I heard Allah's Messenger (ﷺ) saying, "Near the Hour you will fight with people who will wear hairy shoes; and you will also fight people with flat faces like shields."