Sahih Muslim 2532 b
Abu Sa'id Khudri reported Allah's Messenger (ﷺ) as saying:
There would come to the people a time when a detachment would be sent for fighting in the cause of Allah and they would say: See, if you can find amongst them someone from amongst the Companions of Allah's Apostle (ﷺ). They would find a person and they would be granted victory because of him. Then a second detachment would be sent to them and they would say: Do you find amongst them one who had had the privilege of seeing the Companions of the Messenger of Allah (ﷺ)? -and the victory would be granted to them because of him. Then the third detachment would be sent and it would be said to them: See, if you find amongst them (who had had the honour of seeing one) who saw those who saw the Companions of Allah's Apostle (ﷺ). Then the fourth detachment would be sent and it would be said to them: See it you find amongst them one who had the privilege (of seeing) one who saw those who saw those who saw the Companions of Allah's Apostle (ﷺ), and a person would be found and they would be granted victory because of him.
حَدَّثَنِي سَعِيدُ بْنُ يَحْيَى بْنِ سَعِيدٍ الأُمَوِيُّ، حَدَّثَنَا أَبِي، حَدَّثَنَا ابْنُ جُرَيْجٍ، عَنْ أَبِي،
 الزُّبَيْرِ عَنْ جَابِرٍ، قَالَ زَعَمَ أَبُو سَعِيدٍ الْخُدْرِيُّ قَالَ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم
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"‏ يَأْتِي عَلَى النَّاسِ زَمَانٌ يُبْعَثُ مِنْهُمُ الْبَعْثُ فَيَقُولُونَ انْظُرُوا هَلْ تَجِدُونَ فِيكُمْ أَحَدًا مِنْ
 أَصْحَابِ النَّبِيِّ صلى الله عليه وسلم فَيُوجَدُ الرَّجُلُ فَيُفْتَحُ لَهُمْ بِهِ ثُمَّ يُبْعَثُ الْبَعْثُ الثَّانِي
 فَيَقُولُونَ هَلْ فِيهِمْ مَنْ رَأَى أَصْحَابَ النَّبِيِّ صلى الله عليه وسلم فَيُفْتَحُ لَهُمْ بِهِ ثُمَّ يُبْعَثُ
 الْبَعْثُ الثَّالِثُ فَيُقَالُ انْظُرُوا هَلْ تَرَوْنَ فِيهِمْ مَنْ رَأَى مَنْ رَأَى أَصْحَابَ النَّبِيِّ صلى الله عليه
 وسلم ثُمَّ يَكُونُ الْبَعْثُ الرَّابِعُ فَيُقَالُ انْظُرُوا هَلْ تَرَوْنَ فِيهِمْ أَحَدًا رَأَى مَنْ رَأَى أَحَدًا رَأَى
 أَصْحَابَ النَّبِيِّ صلى الله عليه وسلم فَيُوجَدُ الرَّجُلُ فَيُفْتَحُ لَهُمْ بِهِ ‏"‏ ‏.‏