"We entered upon Jabir bin 'Abdullah and I said: 'Tell me about the Hajj of the Prophet. He said: 'The Messenger of Allah stoned the Jamart which is by the tree, with seven pebbles, saying the Takbir with eeach pebble - pebbles that were the size of data stones or fingertips. And he threw them for the bottom of the valley, then he went to the place of sacrifice in Mina."' (Using translation from Nasāʾī 3076)  

أَخْبِرْنِي عَنْ حَجَّةِ النَّبِيِّ ﷺ فَقَالَ إِنَّ رَسُولَ اللهِ ﷺ «رَمَى الْجَمْرَةَ الَّتِي عِنْدَ الشَّجَرَةِ بِسَبْعِ حَصَيَاتٍ يُكَبِّرُ مَعَ كُلِّ حَصَاةٍ مِنْهَا حَصَى الْخَذْفِ رَمَى مِنْ بَطْنِ الْوَادِي ثُمَّ انْصَرَفَ إِلَى الْمَنْحَرِ فَنَحَرَ»  

"We returned during the Hajj with the Prophet and some of us said that they had stoned (the Jamarat) with seven stones, and other said that they had done so with six, and no one denounced anyone else." (Using translation from Nasāʾī 3077)  

سَعْدٌ رَجَعْنَا فِي الْحِجَّةِ مَعَ النَّبِيِّ ﷺ وَبَعْضُنَا يَقُولُ رَمَيْتُ بِسَبْعٍ وَبَعْضُنَا يَقُولُ رَمَيْتُ بِسِتٍّ فَلَمْ يَعِبْ بَعْضُهُمْ عَلَى بَعْضٍ  

I asked Ibn Abbas about a thing concerning the throwing of stones at the jamrahs. He said: I do not know whether the Messenger of Allah ﷺ threw six or seven pebbles. (Using translation from Abū Dāʾūd 1977)  

مَا أَدْرِي «رَمَاهَا رَسُولُ اللهِ ﷺ بِسِتٍّ أَوْ بِسَبْعٍ»