صَحِيحُ مُسْلِمٍ
Sahih Muslim 1963
The Book of Sacrifices
The age of sacrificial animals
حَدَّثَنَا أَحْمَدُ بْنُ يُونُسَ، حَدَّثَنَا زُهَيْرٌ، حَدَّثَنَا أَبُو الزُّبَيْرِ، عَنْ جَابِرٍ، قَالَ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم لاَ تَذْبَحُوا إِلاَّ مُسِنَّةً إِلاَّ أَنْ يَعْسُرَ عَلَيْكُمْ فَتَذْبَحُوا جَذَعَةً مِنَ الضَّأْنِ .
Jabir reported Allah's Messenger (ﷺ) as saying: Sacrifice only a grown-up animal, unless it is difficult for you, in which case sacrifice a ram (of even less than a year, but more than six months' age).
Sahih Muslim, 1963Sahihصحيح