"If anyone tells you that the Messenger of Allah urinated while standing, do not believe him, for I (always) saw him urinating while sitting down."  

أَنَّ رَسُولَ اللَّهِ ﷺ بَالَ قَائِمًا فَلاَ تُصَدِّقْهُ أَنَا رَأَيْتُهُ يَبُولُ قَاعِدًا  

"The Messenger of Allah saw me urinating while standing, and he said: 'O 'Umar, do not urinate standing up.' So I never urinated whilst standing after that."  

رَآنِي رَسُولُ اللَّهِ ﷺ وَأَنَا أَبُولُ قَائِمًا فَقَالَ يَا عُمَرُ لاَ تَبُلْ قَائِمًا فَمَا بُلْتُ قَائِمًا بَعْدُ  

"The Messenger of Allah forbade us to urinate while standing." (Da'if) I heard Muhammed bin Yazid, Abu 'Abdullah, say: "I heard Ahmad bin 'Abdur-Rahman Al-Makhzumi say: 'Sufyan Ath-Thawri said concerning the Hadith of 'Aisha- 'I (always) saw him urinating whilst sitting down' - a man knows more about that (about such matters) than she.' Ahmad bin 'Abdur-Rahman said: 'It was the custom of the Arabs to urinate standing up. Do you not see that in the Hadith of 'Abdur-Rahman bin Hasanah it was said: 'He sits down to urinate as a woman does.'"  

نَهَى رَسُولُ اللَّهِ ﷺ أَنْ يَبُولَ قَائِمًا سَمِعْتُ مُحَمَّدَ بْنَ يَزِيدَ أَبَا عَبْدِ اللَّهِ يَقُولُ سَمِعْتُ أَحْمَدَ بْنَ عَبْدِ الرَّحْمَنِ الْمَخْزُومِيَّ يَقُولُ قَالَ سُفْيَانُ الثَّوْرِيُّ فِي حَدِيثِ عَائِشَةَ أَنَا رَأَيْتُهُ يَبُولُ قَاعِدًا قَالَ الرَّجُلُ أَعْلَمُ بِهَذَا مِنْهَا قَالَ أَحْمَدُ بْنُ عَبْدِ الرَّحْمَنِ كَانَ مِنْ شَأْنِ الْعَرَبِ الْبَوْلُ قَائِمًا أَلاَ تَرَاهُ فِي حَدِيثِ عَبْدِ الرَّحْمَنِ ابْنِ حَسَنَةَ يَقُولُ قَعَدَ يَبُولُ كَمَا تَبُولُ الْمَرْأَةُ