Musnad Ahmad 1153:193

Isma'il narrated to us, he said: Bard ibn Sinan informed us, from 'Ubadah ibn Nusayy, from Ghudayf ibn al-Harith, who said: I said to 'Aishah: "Tell me, did the Messenger of Allah, peace and blessings of Allah be upon him, perform ghusl (ritual bath) for janabah (major ritual impurity) at the beginning of the night or at the end of it?" She said: "Sometimes he performed ghusl at the beginning of the night, and sometimes he performed ghusl at the end of it." I said: "Allah is the Greatest. Praise be to Allah who has made the matter flexible." I said: "Tell me, did the Messenger of Allah, peace and blessings of Allah be upon him, perform witr (the odd-numbered prayer) at the beginning of the night or at the end of it?" She said: "Sometimes he performed witr at the beginning of the night, and sometimes he performed witr at the end of it." I said: "Allah is the Greatest. Praise be to Allah who has made the matter flexible." I said: "Tell me, did the Messenger of Allah, peace and blessings of Allah be upon him, recite the Quran aloud or silently?" She said: "Sometimes he recited it aloud, and sometimes he recited it silently." I said: "Allah is the Greatest. Praise be to Allah who has made the matter flexible."