Sahih Bukhari, Chapter: Witnesses

The Prophet (SAW) heard a man (reciting Quran) in the Mosque, and he said, "May Allah bestow His Mercy upon him. No doubt, he made me remember such-and such Verses of such-and-such Sura which I dropped (from my memory). Narrated Aisha: The Prophet (SAW) performed the Tahajjud prayer in my house, and then he heard the voice of Abbad who was praying in the Mosque, and said, "O Aisha! Is this Abbad's voice?" I said, "Yes." He said, "O Allah! Be merciful to Abbad!"