Abd al-Rahman bin Ma'qil said: A man came to Ibn Abbas (may Allah be pleased with them both) and said to him: What do you say about the grandfather? Ibn Abbas (may Allah be pleased with them both) said: There is no grandfather. Which father of yours is the oldest? The man fell silent and gave him no answer, as though he was unable to answer. Abd al-Rahman said: I said: Adam. Ibn Abbas said: Have you not heard the saying of Allah: "O children of Adam" [Surah al-A'raf: 26]?
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الفرائض / 12424