Sahih Muslim , Book 43, Hadith 62 (In-Book) ⓘ

'Amir b. Sa'd b. Abu Waqqas reported: I wrote (a letter) to Jabir b. Samura (and it was sent) through my servant Nafi' asking him to inform me about something (pertaining to the Haud Kauthar). He wrote to me: I heard him (the Holy Prophet) say: I shall be there ahead of you at the Haud Kauthar.

حَدَّثَنَا قُتَيْبَةُ بْنُ سَعِيدٍ، وَأَبُو بَكْرِ بْنُ أَبِي شَيْبَةَ قَالاَ حَدَّثَنَا حَاتِمُ بْنُ إِسْمَاعِيلَ، عَنِ الْمُهَاجِرِ بْنِ مِسْمَارٍ، عَنْ عَامِرِ بْنِ سَعْدِ بْنِ أَبِي وَقَّاصٍ، قَالَ كَتَبْتُ إِلَى جَابِرِ بْنِ سَمُرَةَ مَعَ غُلاَمِي نَافِعٍ أَخْبِرْنِي بِشَىْءٍ، سَمِعْتَهُ مِنْ، رَسُولِ اللَّهِ صلى الله عليه وسلم - قَالَ - فَكَتَبَ إِلَىَّ إِنِّي سَمِعْتُهُ يَقُولُ ‏ "‏ أَنَا الْفَرَطُ عَلَى الْحَوْضِ ‏" ‏ ‏.‏