Shurayh bin Hani narrates from Aishah (may Allah be pleased with her): I asked Aishah (may Allah be pleased with her) about the prayer of the Prophet (peace and blessings be upon him), and she said: The Prophet (peace and blessings be upon him) would pray the Isha prayer, then come to me and pray four or six rak'ahs. Once it rained at night, so we spread out a mat for him (peace and blessings be upon him); it is as though I am looking at a hole in that mat from which water was gushing out. And I never saw him (peace and blessings be upon him) keeping his clothes from touching the ground.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصلاة / 4508