It was narrated that ‘Ali (رضي الله عنه) said: A male or female mule was given to the Messenger of Allah (ﷺ) as a gift. I said: What is this? He said: `A mule.` I said: Where does it come from? He said: `From mating a male donkey with a mare, and this is what is produced.` I said: Should we mate with ? He said: `No, this is only done by those who do not know.”
Source: sunnah.com
Other translations
Arabic
حَدَّثَنَا يَحْيَى بْنُ آدَمَ، حَدَّثَنَا شَرِيكٌ، عَنْ عُثْمَانَ بْنِ أَبِي زُرْعَةَ، عَنْ سَالِمِ بْنِ أَبِي الْجَعْدِ، عَنْ عَلِيِّ بْنِ عَلْقَمَةَ، عَنْ عَلِيٍّ، رَضِيَ اللَّهُ عَنْهُ قَالَ أُهْدِيَ لِرَسُولِ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ بَغْلٌ أَوْ بَغْلَةٌ فَقُلْتُ مَا هَذَا قَالَ بَغْلٌ أَوْ بَغْلَةٌ قُلْتُ وَمِنْ أَيِّ شَيْءٍ هُوَ قَالَ يُحْمَلُ الْحِمَارُ عَلَى الْفَرَسِ فَيَخْرُجُ بَيْنَهُمَا هَذَا قُلْتُ أَفَلَا نَحْمِلُ فُلَانًا عَلَى فُلَانَةَ قَالَ لَا إِنَّمَا يَفْعَلُ ذَلِكَ الَّذِينَ لَا يَعْلَمُونَ.
sunnah.com