Allah said:

(...the well-known months.)

Al-Bukhari said that Ibn `Umar said that these are Shawwal, Dhul-Qa`dah and the first ten days of Dhul-Hijjah. This narration for which Al-Bukhari did not mention the chain of narrators, was collected by a continuous chain of narrators that Ibn Jarir rendered authentic, leading to Ibn `Umar, who said:

(The Hajj (pilgrimage) is (in) the well-known (lunar year) months.) "which are Shawwal, Dhul-Qa`dah and the (first) ten days of Dhul-Hijjah.'' Its chain is Sahih. Al-Hakim also recorded it in his Mustadrak, and he said, "It meets the criteria of the Two Shaykhs."

This statement is also reported from `Umar, `Ali, Ibn Mas`ud, `Abdullah bin Az-Zubayr, Ibn `Abbas, `Ata', Tawus, Mujahid, Ibrahim An-Nakha`i, Imam Ash-Sha`bi, Al-Hasan, Ibn Sirin, Makhul, Qatadah, Ad-Dahhak bin Muzahim, Ar-Rabi` bin Anas and Muqatil bin Hayyan. This opinion was preferred by Ibn Jarir who said, "It is a common practice to call two months and a part of the third month as `months'. This is similar to the Arab's saying, `I visited such and such person this year or this day.' He only visited him during a part of the year and a part of the day. Allah said:

(But whosoever hastens to leave in two days, there is no sin on him.)

In this case, one will only be hastening for one and a half days.''

Allah then said:

(So whosoever intends (Farada) to perform Hajj therein (by assuming Ihram),) meaning that one's assuming the Ihram requires a Hajj, for the person is required to complete the rituals of Hajj after assuming Ihram. Ibn Jarir said that Al-`Awfi said, "The scholars agree that (Farada) `intends' mentioned in the Ayah means it is a requirement and an obligation.'' `Ali bin Abu Talhah said that Ibn `Abbas said:

(So whosoever intends to perform Hajj therein (by assuming Ihram),) refers to those who assume Ihram for Hajj and `Umrah''. `Ata' said, "'Intends', means, assumes the Ihram.'' Similar statements were attributed to Ibrahim, Ad-Dahhak and others.