Qatadah (may Allah have mercy on him) said that Sulayman bin Hisham said to me: "This man - meaning al-Zuhri (may Allah have mercy on him) - does not leave us alone; whatever we eat, he orders us to perform ablution (wudu) for it." I said: "I asked Sa'id bin al-Musayyib (may Allah have mercy on him) about it, and he said: 'When you eat it, it is pure, and there is no ablution upon you for it; and when it comes out of you, it is impure, and ablution is upon you for it.'" He said: "I see that the two of you differ. Is there anyone in the city?" I said: "Yes, the most senior man in the Arabian Peninsula." He asked: "Who?" I said: "Ata (may Allah have mercy on him)." He sent for him and said: "These two have differed before me, so what do you say?" He said: "Jabir bin Abdullah (may Allah be pleased with him) narrated to me that they ate bread and meat with Abu Bakr (may Allah be pleased with him), then he stood up and prayed and did not perform ablution." He said to me: "What do you say about the lifelong grant ('umra)?" I said: "It has reached me from Abu Hurayrah (may Allah be pleased with him) that the Prophet (peace and blessings be upon him) said: 'The 'umra is valid.'" He said: al-Zuhri (may Allah have mercy on him) said: "It is not an 'umra unless it is made for him and his heirs." He then asked Ata (may Allah have mercy on him): "What do you say?" He said: "Jabir bin Abdullah (may Allah be pleased with him) narrated to me that the Prophet (peace and blessings be upon him) said: 'The 'umra is valid.'" Al-Zuhri (may Allah have mercy on him) said: "The caliphs did not rule that way." Ata (may Allah have mercy on him) said: "Rather, Abd al-Malik bin Marwan ruled that way in such-and-such a case."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الهبات / 11978