مُسْنَدُ أَحْمَدَ
Musnad Ahmad 1595
Musnad Abu Ishaq Sa'd bin Abi Waqqas
It was narrated from Muhammad bin Sa"d that his father said: The Messenger of Allah (ﷺ) said: “The month is like this and like this and like this"- meaning twenty-nine,
Musnad Ahmad 1596This is a qawi Isnad, Muslim (1086)]