Musannaf Ibn Abi Shayba 33:96

Abu Khalid al-Ahmar narrated to us, from Humayd, from Anas, that the Messenger of Allah (may Allah bless him and grant him peace) had a she-camel called al-Adba’ which would not be outrun. Then a Bedouin came on a young camel and outran it. This distressed the Muslims, and they said, "O Messenger of Allah, al-Adba’ has been outrun!" The Messenger of Allah (may Allah bless him and grant him peace) said, "It is a right upon Allah that nothing is raised up in it except that He lowers it," meaning the world.