ENOfficial
'Abdullah b. Dinar reported on the authority of Ibn 'Umar that the Messenger of Allah (ﷺ) used to observe prayer on his ride (no matter) in which direction it had its face turned. 'Abdullah b. Dinar said that Ibn 'Umar used to do like that.
Source: sunnah.com
Other translations
Arabic
وَحَدَّثَنَا يَحْيَى بْنُ يَحْيَى، قَالَ قَرَأْتُ عَلَى مَالِكٍ عَنْ عَبْدِ اللَّهِ بْنِ دِينَارٍ، عَنِ ابْنِ عُمَرَ، أَنَّهُ قَالَ كَانَ رَسُولُ اللَّهِ صلى الله عليه وسلم يُصَلِّي عَلَى رَاحِلَتِهِ حَيْثُمَا تَوَجَّهَتْ بِهِ . قَالَ عَبْدُ اللَّهِ بْنُ دِينَارٍ كَانَ ابْنُ عُمَرَ يَفْعَلُ ذَلِكَ .
sunnah.com