‏الصلاة : Hadeeth No:1505 Salim b. 'Abdullah reported on the authority of his father that the Messenger of Allaah (sallAllaahu alayhi wa sallam) used to observe Nafl (supererogatory) prayer on his ride no matter in what direction it turned its face, and he observed Witr too on it, but did not observe obligatory prayer on it....

‏الصلاة : Hadeeth No:2006 This hadith is narrated on the authority of 'Ala' with the same chain of transmitters....