Sahih Muslim , Book 29, Hadith 5634 (USC-MSA) ⓘ
A hadith like this has been reported on the authority of Nafi` with the same chain of transmitters (and the words are): "I think Ibn `Umar said: The seventieth part from Prophecy."
وَحَدَّثَنَاهُ قُتَيْبَةُ، وَابْنُ، رُمْحٍ عَنِ اللَّيْثِ بْنِ سَعْدٍ، ح وَحَدَّثَنَا ابْنُ رَافِعٍ، حَدَّثَنَا ابْنُ، أَبِي فُدَيْكٍ أَخْبَرَنَا الضَّحَّاكُ، - يَعْنِي ابْنَ عُثْمَانَ - كِلاَهُمَا عَنْ نَافِعٍ، بِهَذَا الإِسْنَادِ وَفِي حَدِيثِ اللَّيْثِ قَالَ نَافِعٌ حَسِبْتُ أَنَّ ابْنَ عُمَرَ قَالَ " جُزْءٌ مِنْ سَبْعِينَ جُزْءًا مِنَ النُّبُوَّةِ " .
also referenced under: Book 42, Hadith 22 (In-Book) & Hadith 2265 (Reference)