It is reported from Imam al-Shafi'i (may Allah have mercy on him), concerning the argument of one who argued from the reports of Ali and Ibn Abbas (may Allah be pleased with them both): I said: Should what came from the Messenger of Allah (peace and blessings be upon him) be abandoned for the saying of someone else? He said: No. I said: You have done so, and in addition you have contradicted Ali and Ibn Abbas (may Allah be pleased with them both). You claimed that Sayyiduna Ali (may Allah be pleased with him) said: When a mouse falls into a well, seven or five buckets are to be drawn from it, yet you claimed that it does not become pure except by (drawing) twenty or thirty. And you claimed that Ibn Abbas (may Allah be pleased with them both) drained Zamzam because of a Zanji who fell into it, yet you say that forty or sixty buckets suffice. This is not established from Ali and Ibn Abbas (may Allah be pleased with them both).
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الطهارة / 1271