Mishkat al-Masabih
Mishkat al-Masabih 1069
وَعَنْ عَبْدِ اللَّهِ بْنِ أَرْقَمَ قَالَ: سَمِعْتُ رَسُولَ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسلم يَقُول: «إِذَا أُقِيمَتِ الصَّلَاةُ وَوَجَدَ أَحَدُكُمُ الْخَلَاءَ فَلْيَبْدَأْ بِالْخَلَاءِ» . رَوَاهُ التِّرْمِذِيُّ وَرَوَى مَالِكٌ وَأَبُو دَاوُدَ وَالنَّسَائِيّ نَحوه
Unreviewed translation. All hadiths in this collection are available in five languages. Titles and introductions may remain in Arabic.
ʿAbd Allah ibn Arqam said: “I heard the Messenger of Allah (ﷺ) say: ‘When the prayer is called and one of you needs to relieve himself, let him relieve himself first.’” Al-Tirmidhi transmitted it; Malik, Abu Dawud, and al-Nasaʾi transmitted a similar report.
Notes and open questions — unreviewed
The Arabic uses the euphemism al-khalāʾ (relieving oneself), which is preserved without specifying a bodily need beyond the source wording.