Sahih Ibn Khuzaymah

Hazrat Mirthad narrates that I asked Sayyiduna Abu Dharr (may Allah be pleased with him), I said, "Did you ask the Messenger of Allah (peace and blessings be upon him) about Laylat al-Qadr?" He replied, "I was the person who asked the most about Laylat al-Qadr." He says, I said, "O Messenger of Allah, tell me, is Laylat al-Qadr in the blessed month of Ramadan or in some other month?" He (peace and blessings be upon him) said, "Rather, it is in Ramadan." I submitted, "O Messenger of Allah, does Laylat al-Qadr occur only in the times of the noble Prophets, and when the Prophets pass away, is Laylat al-Qadr also taken away? Or will it remain until the Day of Judgment?" He (peace and blessings be upon him) said, "No, rather it will remain until the Day of Judgment." I asked, "O Messenger of Allah, is it in Ramadan?" He (peace and blessings be upon him) said, "Seek it in the first and last ten nights." He says, then he continued to explain to the people, so I took advantage of his unawareness and submitted, "O Messenger of Allah, I ask you by oath, in which twenty nights is it?" The Messenger of Allah (peace and blessings be upon him) became so angry with me that he had never been so angry before nor after. Then he (peace and blessings be upon him) said, "Indeed, if Allah had willed, He would have informed you of it. Seek it in the last seven nights."