It is narrated from Sayyiduna Abu Hurayrah (may Allah be pleased with him) that he (peace and blessings be upon him) said: "When any of you gets up from sleep, let him pour water over his hands before putting them into the vessel." Qays al-Ashja'i said to him: "When we come to this mihras (stone basin) of yours, what should we do with it?" Sayyiduna Abu Hurayrah (may Allah be pleased with him) said: "I seek refuge in Allah from your evil."
Abu Ubayd says that al-Asma'i said: The mihras is a huge, elongated, hollowed-out stone like a cistern, from which people perform ablution; none of you is able to move it.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الطهارة / 215