Hastening to depart in two days

Q: I learned that there are three nights in Mina. The pilgrim has to spend just two nights in Mina if he has intended to leave early or to spend three nights if he has not intended to leave early. This view is mentioned in the books of Fiqh (Islamic jurisprudence) such as Muntah Al-Iradat, Al-Rawdh Al-Murbi` Sharh Zad Al-Mustaqni` and it is also mentioned in the interpretation of the Qur`anic verse: But whosoever hastens to leave in two days, there is no sin on him and whosoever stays on, there is no sin on him In his book of Tafsir (explanation/exegesis of the meanings of the Qur'an), Ibn Kathir mentioned it and so does one of the appointed Muftis who says that it is not permissible for the person who has intended to leave quickly, to leave Makkah before the third day of `Eid-ul-Adha (the Festival of the Sacrifice). This Mufty also adds that it is permissible to slaughter the Ud-hiyahs (sacrificial animal offered by non-pilgrims) on the fourth day. In this case, the view of Al-Mughni agrees with the views mentioned in the books that were mentioned previously. If these views are all based on authentic narrations, how can we reconcile these views and the Hadith that was narrated by Imam Ahmad, and Ahl-ul-Sunan (authors of Hadith compilations classified by jurisprudential themes) with an authentic Isnad (chain of narrators) that the Prophet (peace be upon him) said: The period of halting at Mina is three days. Then, whoever hastens (his departure) by two days, it is no sin for him, and whoever delays it there is no sin on him. This Hadith, as far as I know, yet Allah knows best, indicates that it is permissible for the pilgrim who has intended to hasten in leaving Makkah to leave on the second day of `Eid-ul-Adha. This is because the Hadith said, 'The period of halting at Mina is three days..." and not: 'The period of halting at Mina are three nights...' as mentioned in Al-Mughni and in the books mentioned above.