Sahih Muslim Book 7, Hadith Number 3007.

Chapter : Excellence of making a halt at al Muha’ab, on the day of Nahr, and observing prayer there.

Nafi’ reported that Ibn ‘Umar regarded halt at Muhassab as Sunnah (of the Holy Prophet) and observed the noon prayer on Yaum al-Nafr at that place. Nafi’ said: Allah’s Messenger (may peace be upon him) halted at Muhassab and the Caliphs did the same after him.