Abu Dawud

Benefits and Issues:
The animal born from the mating of a donkey and a mare is called a mule.
Allah, the Exalted and Most High, has also mentioned it among His blessings.
(“And [He created] horses, mules, and donkeys for you to ride and as an adornment. And He creates that which you do not know.”) ( an-Nahl: 8)
Allah, the Exalted, created horses, mules, and donkeys,
so that you may ride them, and they are also a source of adornment for you.
The Messenger of Allah (sallallahu alayhi wa sallam) also rode a mule.
If the creation of the mule were impermissible, it would neither be counted among the divine blessings nor would the Noble Prophet (sallallahu alayhi wa sallam) have ridden it.
Therefore, the scholars have interpreted the hadith in which the mating of a donkey and a mare is considered disliked
as referring to desirability (i.e., that refraining from it is preferred).
That is, it is not a preferred act.
However, its permissibility remains.

(1) A mule is produced from the mating of a mare and a donkey, but in this hadith, such mating has been regarded as disliked. However, in the Noble Qur’an, the mule is mentioned along with the horse and the donkey as a favor, from which the existence of the mule and its continuation as a species is deemed permissible. Therefore, the scholars have considered the prohibition or the ruling of dislike in this hadith to be of a non-binding (tanzihi) nature, or it will be interpreted as applying to the situation where, due to this, the lineage and increase of horses is affected, because the horse is more beneficial and necessary than the mule; its lineage should not be diminished.

(2) Declaring this to be the work of the ignorant means only to discourage the breeding of mules. Some scholars have said that one should not do this act oneself; however, the use of mules is permissible.