Narrated 'Ubai bin `Umar: Abu Musa asked permission to enter upon `Umar, but seeing that he was busy, he went away. `Umar then said, "Didn't I hear the voice of `Abdullah bin Qais? Allow him to come in." He was called in and `Umar said to him, "What made you do what you did." He replied, "We have been instructed thus by the Prophet" `Umar said, "Bring proof (witness) for this, other wise I will do so-and-so to you." Then `Abdullah bin Qais went to a gathering of the Ansar who then said, "None but the youngest of us will give the witness for it." So Abu Sa`id Al-Khudri got up and said, "We used to be instructed thus (by the Prophet)." `Umar said, "This tradition of the Prophet remained hidden from me. Business in the market kept me busy."

Narrated Al-A'raj: Abu Huraira said, "You people claim that Abu Huraira narrates many narrations of Allah's Apostle. (Anyhow) with Allah will be our appointment. I was a poor man, and used to stick to Allah's Apostle contented with what will fill my stomach, and the Muhajirin (emigrants) used to be busy trading in the markets, and the Ansar used to be busy looking after their properties. One-day I heard Allah's Apostle saying, 'Who will spread his Rida' (a garment covering the upper part of the body) till I finished my speech and then fold it, (i.e. wrap it over your body), in which case he will never forget anything he had heard from me." So I spread my garment which I was wearing; and by Him Who sent Muhammad with the Truth, ever since, I have never forgotten whatever I heard from him (the Prophet)" (See, Hadith No. 119, Vol. 1)