Ziyad bin Abd al-Rahman al-Nakha'i narrates: We were sitting with Sayyiduna Ali (may Allah be pleased with him) in the great mosque of Kufah, at a time when Kufah consisted of reed huts. The mu'adhdhin came and said: "O Commander of the Believers, the time of the Asr prayer has come." He said: "Sit down." So he sat down. Then he came again and said the same thing, so Sayyiduna Ali (may Allah be pleased with him) said: "This dog is teaching us the Sunnah!" Then he stood up and led us in the Asr prayer. When we returned to the place where we had been sitting, we sat down on our knees, and the sun was inclining towards setting, and we were watching it. This hadith has a sahih (authentic) chain; the two Shaykhs (Bukhari and Muslim) used all of its narrators as evidence, yet they did not record it.