Fiqh-us-Sunnah Volume 5, Hajj and ‘Umrah, Fiqh 5.027.

This refers to the specific period of time when the rites of Hajj have to be performed to be valid. This is clear from the words of Allah: “They ask you concerning the new moons. Say: They are but signs to mark fixed periods of time (in the affairs of) men, and for Hajj” l and “For Hajj are the months well-known.” (Qur’an 2.197) The Muslim scholars are agreed that the months of Hajj are the months of Shawwal and Zhul-Qui’dah. They differ about the month of Zhul-Hijjah, whether only the first ten days of it are included in the months of Hajj or the entire month. Ibn ‘Umar, Ibn ‘Abbas, Ibn Mas’ud, the Hanafi and Shafi’i school, and Ahmad are of the opinion that only its first ten days are included in the months of Hajj, while Malik holds the entire month of ZhulHijjah as one of the Hajj months. Ibn Hazm supports Malik’s opinion, saying that the words, “For Hajj are the months well-known,” does not mean two months and a part of other months.

Similarly we know that of the rites of Hajj, the throwing of pebbles at jamarah takes place on the 13th of Zhul-Hijjah, while the scholars agree that the circumambulation of Ifadah, which is one of the essential rites of Hajj, may be performed anytime in the month of Zhul-Hijjah. There is no disagreement on this point. It is, therefore, quite correct to say that all three months are the months of Hajj.

The effects of disagreement are apparent mainly in the rites performed after slaughtering the sacrificial animal. Those who consider the entire month of Zhul-Hijjah a Hajj month, hold there is no penalty for delay in slaughtering an animal. On the other hand, those who hold that only its first ten days are included in the period of Hajj are of the opinion that such a person must offer a penalty and offer a sacrifice for delay.