Sulayman bin Farrukh says: I met Abu Ayyub (may Allah be pleased with him) and shook hands with him. He found my nails long and said: A man came to the Prophet (peace and blessings be upon him) and asked about the news of the heavens (revelation). The Messenger of Allah (peace and blessings be upon him) said: "One of you asks about the news of the heavens while he leaves his nails like the talons of birds, in which janabah (impurity) and dirt collect."
(b) These are the words of al-Asfati; a large group narrates it in this way from the narrator Qurash. Abu Dawud al-Tayalisi (may Allah have mercy on him) also recorded this hadith.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الطهارة / 828