Narrated Anas bin Malik: Whenever the Prophet (saws) started on a journey before noon, he used to delay the Zuhr prayers till the time for the 'Asr prayer and then he would dismount and offer them together; and whenever the sun declined before he started on a journey he used to offer the Zuhr prayers and then ride (for journey).
Hadith Referenceصحيح البخاري / كتاب تقصير الصلاة / 1112
Hadith Gradingمحدثین:أحاديث صحيح البخاريّ كلّها صحيحة