Sahih Bukhari Volume 008, Book 076, Hadith Number 508.

Narated By Anas : The Prophet had a she-camel called Al'Adba' and it was too fast to surpass in speed. There came a Bedouin riding a camel of his, and that camel outstripped it (i.e. Al-Aqba'). That result was hard on the Muslims who said sorrowfully, "Al- Adba has been outstripped." Allah's Apostle said, "It is due from Allah that nothing would be raised high in this world except that He lowers or puts it down."