Sahih Muslim Book - 1, Hadith - 526

حَدَّثَنَا قُتَيْبَةُ بْنُ سَعِيدٍ حَدَّثَنَا عَبْدُ الْعَزِيزِ يَعْنِي ابْنَ أَبِي حَازِمٍ عَنْ أَبِي حَازِمٍ عَنْ سَهْلِ بْنِ سَعْدٍ أَنَّ رَسُولَ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ قَالَ لَيَدْخُلَنَّ الْجَنَّةَ مِنْ أُمَّتِي سَبْعُونَ أَلْفًا أَوْ سَبْعُمِائَةِ أَلْفٍ لَا يَدْرِي أَبُو حَازِمٍ أَيَّهُمَا قَالَ مُتَمَاسِكُونَ آخِذٌ بَعْضُهُمْ بَعْضًا لَا يَدْخُلُ أَوَّلُهُمْ حَتَّى يَدْخُلَ آخِرُهُمْ وُجُوهُهُمْ عَلَى صُورَةِ الْقَمَرِ لَيْلَةَ الْبَدْرِ.

It was narrated from Sahl bin Sa'd that the Messenger of Allah (s.a.w) said: "Seventy thousand or seven hundred thousand" - Abu Hazim did not know which of them he said - "of my Ummah will enter Paradise, supporting one another and holding on to one another; the first of them will not enter until the last of them does so (i.e. they will all enter in a row, showing the width of gate of Paradise), and their faces will be like the moon when it is full."