Hadith Q236

فَيُضَيِّقُ الزِّيَادَةَ فِيهِ أَوِ النُّقْصَانَ مِنْهُ، وَالدَّلِيلُ عَلَى أَنَّ الْوَاجِبَ عَلَى الْمُغْتَسِلِ إِمْسَاسُ الْمَاءِ جَمِيعَ الْبَدَنِ قَلَّ الْمَاءُ أَوْ كَثُرَ‏.‏ قَالَ أَبُو بَكْرٍ: خَبَرُ عَائِشَةَ «كُنْتُ أَغْتَسِلُ أنَا وَرَسُولَ اللَّهِ صَلَّى اللهُ عَلَيْهِ وَسَلَّمَ مِنْ إِنَاءٍ وَاحِدٍ»
That he should feel discomfort in increasing or decreasing it, and the explanation of the evidence that it is obligatory for a person in a state of major impurity (janabah) to pour water over the entire body, whether the water is little or much. Imam Abu Bakr, may Allah have mercy on him, says that in the hadith of Lady Aisha, may Allah be pleased with her, it is mentioned that "I and the Messenger of Allah, peace and blessings be upon him, used to perform ghusl from the same vessel."
Hadith Reference صحيح ابن خزيمه / جماع أبواب غسل الجنابة / Q236