A man asked, "Messenger of Allah, was Adam a prophet?"He replied, "Yes, one to whom Allah spoke."The man asked, "How long was there between him and Nuh?"He answered, "Ten generations."
أن رجلا قال: يا رسول الله أنبي كان آدم؟ قال: نعم مكلم قال: فكم كان بينه وبين نوح؟ قال: عشرة قرون.
Ibn Hibban (6190) narrated it from Muhammad bin Yusuf, who said, Muhammad bin Abdul-Malik bin Zanjawayh told us, Abu Tuba told us, Muawiya bin Salam told us, from his brother Zayd bin Salam, who said, I heard Abu Salam say, I heard Abu Umama mention it, and its sourcing was already covered in the Book of Faith.It has also been narrated with a sahih chain from Ibn Abbas in similar wording, as a statement attributed to him rather than to the Prophet. Tabari narrated it in his Tarikh (1/178) from Muhammad bin Bashshar, who said, Abu Dawud told us, Hammam told us, from Qatada, from Ikrima, from Ibn Abbas, who said, "Between Nuh and Adam, peace be upon them, there were ten generations, all of them following a path of truth, then they differed, so Allah sent the prophets as bringers of good news and warners."The word "generation" here is meant as a hundred years, which is the most immediate understanding, though it has also been said to mean a generation of people. The generation before Nuh lived very long lives, just as Nuh himself lived a thousand years minus fifty . So the meaning of "ten generations" would be ten generations of people, spanning thousands of years.