Hadith
أَخْبَرَنَا مُحَمَّدُ بْنُ الْمُثَنَّى، قَالَ حَدَّثَنَا ابْنُ أَبِي عَدِيٍّ، عَنِ ابْنِ عَوْنٍ، قَالَ حَدَّثَنَا جَمِيلٌ، عَنْ أَبِي الْمَلِيحِ، عَنْ نُبَيْشَةَ، قَالَ ذُكِرَ لِلنَّبِيِّ صلى الله عليه وسلم قَالَ كُنَّا نَعْتِرُ فِي الْجَاهِلِيَّةِ . قَالَ " اذْبَحُوا لِلَّهِ عَزَّ وَجَلَّ فِي أَىِّ شَهْرٍ مَا كَانَ وَبَرُّوا اللَّهَ عَزَّ وَجَلَّ وَأَطْعِمُوا " .
It was narrated that Nubaishah said:"It was said to the prophet: 'During the Jahiliyyah we used to offer the 'Atirah.' He said: 'Slaughter for the sake of Allah, the Mighty and sublime, no matter what month it is; do good for the sake of Allah, the Mighty and sublime, and feed the poor
Sahih · Abu Ghuddah
Sunan an-Nasa'i 4228 ·Book 41, Hadith 7·Also available on sunnah.com·