Ayam-e-Tashriq (ایام تشریق)
The days fixed for animal sacrifice are the same as have been appointed for the stay at Mina once the pilgrims return from Muzdalifah. Pilgrims can return from Mina on the 12th of Dhu al-Hajj and can also stay on till the 13th. The Almighty has said that both cases will incur no sin . In Surah Hajj, the words أَيَّامٍ مَّعْلُومَاتٍ (some appointed days (22:28)), allude to these very days. In religious parlance, they are called “ the days of tashriq ”. Besides animal sacrifice in these days, one is also required to declare the takbir at the end of each congregational prayer . Being an absolute directive, the words of the takbir have not been fixed. The reason for this is that the extent of stay does not hold real significance; what does hold real significance is whether the time of stay however much it be was spent in the remembrance of God or not: وَاذْكُرُواْ اللّهَ فِي أَيَّامٍ مَّعْدُودَاتٍ فَمَن تَعَجَّلَ فِي يَوْمَيْنِ فَلاَ إِثْمَ عَلَيْهِ وَمَن تَأَخَّرَ فَلا إِثْمَ عَلَيْهِ لِمَنِ اتَّقَى وَاتَّقُواْ اللّهَ وَاعْلَمُوا أَنَّكُمْ إِلَيْهِ تُحْشَرُونَ (2: 203 ) And remember God in these few appointed days [at Mina]. He who is in haste and departs on the second day incurs no sin, nor does he who stays on longer. [Yes, but] for those who truly fear God and have fear of God, and be aware that [one day] you shall all be gathered before Him. (2:203)