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 ‏"‏ ‏.‏
Translation
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).

Comment

The Book of Sacrifices - Sahih Muslim 1963

"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)."

Primary Ruling on Sacrificial Animals

The preferred and complete fulfillment of the sacrifice is with a mature animal (thaniyyah), which for camels is five years, cows two years, goats one year, and sheep six months. This represents the ideal offering that achieves the intended spiritual benefit.

Concession for Difficulty

Islamic law provides ease and removes hardship. If obtaining a mature animal causes genuine difficulty - whether financial, availability, or other legitimate constraints - one may sacrifice a jadha' (ram between six months and one year). This demonstrates the Shariah's balance between ideal practice and practical consideration of circumstances.

Legal Wisdom Behind Age Specifications

The requirement for maturity ensures the sacrifice represents meaningful giving, as mature animals have greater value. The concession for rams maintains the spirit of sacrifice while accommodating necessity. This ruling reflects the principle that acts of worship should be performed according to one's capability without causing undue hardship.

Scholarly Consensus

This hadith establishes one of the fundamental conditions for udhiyah (sacrifice). The majority of scholars hold that sacrificing animals younger than the specified ages is invalid, except for sheep at six months which are considered equivalent to one-year-olds due to their rapid growth and development.