On the description of the Day of Sacrifice
Nahj al-Balāgha|Volume 1|Book 1|Chapter 53
وَ مِنْ تَمامِ الاْضْحِيَّةِ اسْتِشْرافُ اُذُنِها، وَ سَلامَةُ عَيْنِها. فَاِذا سَلِمَتِ الاْذُنُ وَالْعَيْنُ سَلِمَتِ الاْضْحِيَّةُ وَ تَمَّتْ، وَلَوْ كانَتْ عَضْباءَ لْقَرْنِ تَجُرُّ رِجْلَها اِلَى الْمَنْسَكِ.
For an animal to be fully fit for sacrifice it is necessary that both its ears should be raised upwards and its eyes should be healthy. If the ears and the eyes are sound the animal of sacrifice is sound and perfect, even though its horn be broken or it drags its feet to the place of sacrifice.