Mishkat al-Masabih 27 Fitan كتاب الفتن 133

وَعَنْ عَائِشَةَ قَالَتْ: كَانَ رِجَالٌ مِنَ الْأَعْرَابِ يَأْتُونَ النَّبِيَّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ فَيَسْأَلُونَهُ عَنِ السَّاعَةِ فَكَانَ يَنْظُرُ إِلَى أصغرِهم فَيَقُول: «إِنْ يَعِشْ هَذَا لَا يُدْرِكْهُ الْهَرَمُ حَتَّى تَقُومَ عَلَيْكُمْ سَاعَتُكُمْ» . مُتَّفَقٌ عَلَيْهِ

`A’isha told that when nomadic Arabs came and asked the Prophet about the last hour, he would look at the youngest of them and say, “If this one lives, he will not become decrepit before your hour comes to you.” (Bukhari and Muslim.)