Maliks Muwatta Book 009, Hadith Number 001.

Section : Joining Two Prayers when Settled and when Travelling.

Yahya related to me from Malik from Da'ud ibn al-Husayn from al-Araj from Abu Hurayra that the Messenger of Allah, may Allah bless him and grant him peace, joined dhuhr and asr on his journey to Tabuk.