Al-Kāfi - Volume 5 > Advance Payment for Buying Slaves and Animals
Hadith #7

7- أَحْمَدُ بْنُ مُحَمَّدٍ وَعَلِيُّ بْنُ إِبْرَاهِيمَ عَنْ أَبِيهِ جَمِيعاً عَنِ ابْنِ أَبِي عُمَيْرٍ عَنْ أَبِي الْمَغْرَاءِ عَنِ الْحَلَبِيِّ قَالَ سُئِلَ أَبُو عَبْدِ اللهِ (عَلَيْهِ السَّلام) عَنِ الرَّجُلِ يُسْلِمُ فِي وُصَفَاءِ أَسْنَانٍ مَعْلُومَةٍ وَلَوْنٍ مَعْلُومٍ ثُمَّ يُعْطِي دُونَ شَرْطِهِ أَوْ فَوْقَهُ فَقَالَ إِذَا كَانَ عَنْ طِيبَةِ نَفْسٍ مِنْكَ وَمِنْهُ فَلا بَأْسَ.

7. Ahmad ibn Muhammad from and Ali has narrated from his father all from ibn abu ‘Umayr from abu al-Mighra’ from al-Halabiy who has said the following: “Once abu ‘Abd Allah, ‘Alayhi al-Salam, was asked about the case of a man who made an advance payment for things of clearly described age and color; then the party gave him more or less than the set condition. He (the Imam) said, ‘If it is with fine consent it is not unlawful.’”