Mishkat al-Masabih 11 Business Transactions كتاب البيوع 104

وَعَنْ أَنَسٍ: أَنَّ رَجُلًا مِنْ كِلَابٍ سَأَلَ النَّبِيَّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ عَنْ عَسْبِ الْفَحْلِ فَنَهَاهُ فَقَالَ: يَا رَسُولَ اللَّهِ إِنَّا نُطْرِقُ الْفَحْلَ فَنُكْرَمُ فَرَخَّصَ لَهُ فِي الْكَرَامَةِ. رَوَاهُ التِّرْمِذِيّ

Anas said that a man of Kilab asked the Prophet about hiring a stallion to cover a female and he forbade him; but when he said, “Messenger of God, we lend a stallion to cover a female and are given a present,” he gave him licence to accept a present. Tirmidhi transmitted it.