عَن مَرْوَان الْأَصْفَر
قَالَ: «رَأَيْتُ ابْنَ عُمَرَ أَنَاخَ رَاحِلَتَهُ مُسْتَقْبِلَ الْقِبْلَةِ ثُمَّ جَلَسَ يَبُولُ إِلَيْهَا فَقُلْتُ: يَا أَبَا عَبْدِ الرَّحْمَنِ أَلَيْسَ قَدْ نُهِيَ عَنْ هَذَا قَالَ: بلَى إِنَّمَا نُهِيَ عَنْ ذَلِكَ فِي الْفَضَاءِ فَإِذَا كَانَ بَيْنَكَ وَبَيْنَ الْقِبْلَةِ شَيْءٌ يَسْتُرُكَ فَلَا بَأْس»
I saw Ibn Umar make his camel kneel facing the qibla, then sit down and pass water in its direction, so I said, “Abu Abd ar-Rahman, has this not been forbidden?” He replied, “No, that was forbidden only in open country; but when there is something between you and the qibla to conceal you, there is no harm.”
Mishkat al-Masabih 347, Book 4, Purification, Hadith 83. 1 min read