عَنْ جَابِرٍ قَالَ: إِنَّ رَسُولَ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ نَهَى عَنِ الثُّنْيَا إِلَّا أنْ يُعلمَ. 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.