Sahih Bukhari Volume 8, Book 86, Hadith 6846

حَدَّثَنَا إِسْمَاعِيلُ، حَدَّثَنِي مَالِكٌ، عَنْ عَبْدِ الرَّحْمَنِ بْنِ الْقَاسِمِ، عَنْ أَبِيهِ، عَنْ عَائِشَةَ، قَالَتْ جَاءَ أَبُو بَكْرِ ـ رضى الله عنه ـ وَرَسُولُ اللَّهِ صلى الله عليه وسلم وَاضِعٌ رَأْسَهُ عَلَى فَخِذِي فَقَالَ حَبَسْتِ رَسُولَ اللَّهِ صلى الله عليه وسلم وَالنَّاسَ، وَلَيْسُوا عَلَى مَاءٍ‏.‏ فَعَاتَبَنِي، وَجَعَلَ يَطْعُنُ بِيَدِهِ فِي خَاصِرَتِي، وَلاَ يَمْنَعُنِي مِنَ التَّحَرُّكِ إِلاَّ مَكَانُ رَسُولِ اللَّهِ صلى الله عليه وسلم فَأَنْزَلَ اللَّهُ آيَةَ التَّيَمُّمِ‏.‏

Narrated By 'Aisha : Abu Bakr came to me while Allah's Apostle was sleeping with his head on my thigh. Abu Bakr said (to me), "You have detained Allah's Apostle and the people, and there is no water in this place." So he admonished me and struck my flanks with his hand, and nothing could stop me from moving except the reclining of Allah's Apostle (on my thigh), and then Allah revealed the Divine Verse of Tayammum.