Sahih Bukhari Volume 5, Book 64, Hadith 4440

حَدَّثَنَا مُحَمَّدٌ، حَدَّثَنَا عَفَّانُ، عَنْ صَخْرِ بْنِ جُوَيْرِيَةَ، عَنْ عَبْدِ الرَّحْمَنِ بْنِ الْقَاسِمِ، عَنْ أَبِيهِ، عَنْ عَائِشَةَ، دَخَلَ عَبْدُ الرَّحْمَنِ بْنُ أَبِي بَكْرٍ عَلَى النَّبِيِّ صلى الله عليه وسلم وَأَنَا مُسْنِدَتُهُ إِلَى صَدْرِي، وَمَعَ عَبْدِ الرَّحْمَنِ سِوَاكٌ رَطْبٌ يَسْتَنُّ بِهِ، فَأَبَدَّهُ رَسُولُ اللَّهِ صلى الله عليه وسلم بَصَرَهُ، فَأَخَذْتُ السِّوَاكَ فَقَصَمْتُهُ وَنَفَضْتُهُ وَطَيَّبْتُهُ، ثُمَّ دَفَعْتُهُ إِلَى النَّبِيِّ صلى الله عليه وسلم فَاسْتَنَّ بِهِ، فَمَا رَأَيْتُ رَسُولَ اللَّهِ صلى الله عليه وسلم اسْتَنَّ اسْتِنَانًا قَطُّ أَحْسَنَ مِنْهُ، فَمَا عَدَا أَنْ فَرَغَ رَسُولُ اللَّهِ صلى الله عليه وسلم رَفَعَ يَدَهُ أَوْ إِصْبَعَهُ ثُمَّ قَالَ ‏"‏ فِي الرَّفِيقِ الأَعْلَى ‏"‏‏.‏ ثَلاَثًا ثُمَّ قَضَى، وَكَانَتْ تَقُولُ مَاتَ بَيْنَ حَاقِنَتِي وَذَاقِنَتِي‏

Narrated By 'Aisha : 'Abdur-Rahman bin Abu Bakr entered upon the Prophet while I was supporting the Prophet on my chest. 'AbdurRahman had a fresh Siwak then and he was cleaning his teeth with it. Allah's Apostle looked at it, so I took the Siwak, cut it (chewed it with my teeth), shook it and made it soft (with water), and then gave it to the Prophet who cleaned his teeth with it. I had never seen Allah's Apostle cleaning his teeth in a better way. After finishing the brushing of his teeth, he lifted his hand or his finger and said thrice, "O Allah! Let me be with the highest companions," and then died. 'Aisha used to say, "He died while his head was resting between my chest and chin.