Sahih al-Bukhari, Hadith 5473 ⓘ

Narrated Abu Huraira: The Prophet said, "Neither Fara' nor 'Atira (is permissible):" Al-Fara' nor 'Atira (is permissible):" Al- Fara' was the first offspring (of camels or sheep) which the pagans used to offer (as a sacrifice) to their idols. And Al-`Atira was (a sheep which was to be slaughtered) during the month of Rajab.

حَدَّثَنَا عَبْدَانُ، حَدَّثَنَا عَبْدُ اللَّهِ، أَخْبَرَنَا مَعْمَرٌ، أَخْبَرَنَا الزُّهْرِيُّ، عَنِ ابْنِ الْمُسَيَّبِ، عَنْ أَبِي هُرَيْرَةَ ـ رضى الله عنه ـ عَنِ النَّبِيِّ صلى الله عليه وسلم قَالَ ‏ "‏ لاَ فَرَعَ وَلاَ عَتِيرَةَ ‏" ‏‏.‏ وَالْفَرَعُ أَوَّلُ النِّتَاجِ، كَانُوا يَذْبَحُونَهُ لَطِوَاغِيتِهِمْ، وَالْعَتِيرَةُ فِي رَجَبٍ‏.‏