Abdullah bin 'Umar (Allah be pleased with both of them) reported Allah's Messenger (ﷺ) as saying: The month (of Ramadan) is thus and thus, and thus. i. e. ten, ten and-nine.
'Abdul Rahman bin Yazid and al-Aswad bin Yazid reported: We heard 'Abdullah bin Mas'ud saying to the gathering of people (at Muzdalifa) that he had heard Talbiya from him, upon whom Surah al-Baqarah was revealed, at this very place. And so he ('Abdullah bin Mas'ud) pronounced Talbiya and we also pronounced it with him.