All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah and that Muhammad, sallallaahu ʻalayhi wa sallam, is His slave and Messenger.
The Prophet, sallallaahu ʻalayhi wa sallam, said, “Goodness will remain in the forelocks of horses until the Day of Judgment.” It is a saheeh (sound) hadeeth narrated by Al-Bukhari and Muslim and cited in other Hadeeth books as well.
As for your remark, “They are used in many ways,” it should be noted that the words of the Prophet, sallallaahu ʻalayhi wa sallam, do not refer to all kinds of horses; rather, they are confined to those used for jihaad and the like.
An-Nawawi wrote:
“These ahaadeeth imply the recommendation of riding and acquiring horses for the purpose of jihaad and fighting against the enemies of Allaah, underlining that the goodness derived from them and jihaad shall continue unto the Day of Judgment. As for the other hadeeth that reads, 'An evil omen may be found in horses,' it means that horses used for other than jihaad can be a source of a bad omen. It could also mean that horses could be a source of goodness and an evil omen at the same time. Goodness in this context is interpreted as 'rewards and spoils'. This does not negate the fact that some horses may be a source of bad omen as well.” [Sharh Muslim]
Az-Zarqaani wrote:
“A version of the hadeeth cited by (Imaam) Muslim reads, 'People inquired, 'Why is that, O Messenger of Allaah?'' He replied, '(They bring about) rewards and spoils of war.' Hence, it is deduced that though the indication of the hadeeth is general, it is intended to specify horses used for the purpose of jihaad, both those ridden in the actual fighting or those tied up ready to be used for the purpose of jihaad. This is further emphasized by the previously cited hadeeth that reads, 'Horses are kept for one of three purposes...'” [Sharh Al-Muwatta']
Allaah knows best.