مُسْنَدُ أَحْمَدَ
Musnad Ahmad 2636
Musnad of 'Abdullah bin al-'Abbas bin 'Abdul-Muttalib from the Prophet
It was narrated that Ibn 'Abbas (رضي الله عنه) said: The Messenger of Allah (ﷺ) set out from Madinah for Makkah, and he fasted until he reached ‘Usfan, then he called for water. He lifted it up so that the people could see, then he broke his fast until he came to Makkah, and that was in Ramadan. And Ibn 'Abbas used to say: The Messenger of Allah (ﷺ) fasted and did not fast, so whoever wants may fast and whoever wants may not fast.
Musnad Ahmad 2652Its isnad is saheeh, al-Bukhari (1948) and Muslim (1113)]