The Book of Pilgrimage (Kitab Al-Hajj)
Muslim :: Book 7 : Hadith 2757
A'isha (Allah be pleased with her) reported that Allah's Apostle (may peace be upon him) went (to the house of) Duba'a bint al-Zubair b. Abd al-Muttalib. She said: Messenger of Allah, I intend to perform Hajj, but I am ill. Thereupon Allah's Apostle (may peace be upon him) said: Enter Into the state of Ihram on condition that you would abandon it when Allah would detain you.