An-Nahl 16:8 والخيل والبغال والحمير لتركبوها وزينة ويخلق ما لا تعلمون ٨

This refers to another category of animals that Allah has created as a blessing for His servants; horses, mules and donkeys, all of which He made for riding and adornment.

This is the main purpose for which these animals were created. It was reported in the Two Sahihs that Jabir bin `Abdullah said: "