Al-Kāfi - Volume 5 > Advance Payment for Buying Slaves and Animals
Hadith #11

11- مُحَمَّدُ بْنُ يَحْيَى عَنْ أَحْمَدَ بْنِ مُحَمَّدٍ عَنِ ابْنِ مَحْبُوبٍ عَنْ أَبِي أَيُّوبَ عَنْ سَمَاعَةَ قَالَ سُئِلَ أَبُو عَبْدِ اللهِ (عَلَيْهِ السَّلام) عَنِ السَّلَمِ فِي الْحَيَوَانِ فَقَالَ أَسْنَانٌ مَعْلُومَةٌ وَأَسْنَانٌ مَعْدُودَةٌ إِلَى أَجَلٍ مَعْلُومٍ لا بَأْسَ بِهِ.

11. Muhammad ibn Yahya has narrated from Ahmad ibn Muhammad from ibn Mahbub from abu Ayyub from Sama‘ah who has said the following: “Once abu ‘Abd Allah, ‘Alayhi al-Salam, was asked about advance payment to buy animals. He (the Imam) said, ‘The age must be clearly known and the numbers must be made known for the known time, then it is not unlawful.’”