Abdullah bin Abi Labid عبد الله بن أبي لبيد · Fasting (Kitab Al-Siyam)

The Prophet (ﷺ) said: The end of Ramadan is on the day when you end it, and the 'Id (festival) of sacrifice is on the day when you sacrifice. The whole of Arafah is the place of staying, and the whole of Mina is the place of sacrifice, and all the roads of Mecca are the place of sacrifice, and the whole of Muzdalifah is the place of staying.

I asked Sa'id b. Jubair about fasting during Rajab. He said: Ibn 'Abbas told me that the Messenger of Allah (ﷺ) used to fast to such an extent that we thought that he would never break his fast; and he would go without fasting to such an extent that we thought he would never fast.