Urwah reported on the authority of his father that Abdullah ibn al-Arqam travelled for performing hajj (pilgrimage) or umrah. He was accompanied by the people whom he led in prayer. One day when he was leading them in the dawn (fajr) prayer, he said to them: One of you should come forward. He then went away to relieve himself. He said: I heard the Messenger of Allah ﷺ say: When any of you feels the need of relieving himself while the congregational prayer is ready, he should go to relieve himself.  

أَنَّهُ خَرَجَ حَاجًّا أَوْ مُعْتَمِرًا وَمَعَهُ النَّاسُ وَهُوَ يَؤُمُّهُمْ فَلَمَّا كَانَ ذَاتَ يَوْمٍ أَقَامَ الصَّلاَةَ صَلاَةَ الصُّبْحِ ثُمَّ قَالَ لِيَتَقَدَّمْ أَحَدُكُمْ وَذَهَبَ إِلَى الْخَلاَءِ فَإِنِّي سَمِعْتُ رَسُولَ اللَّهِ ﷺ يَقُولُ إِذَا أَرَادَ أَحَدُكُمْ أَنْ يَذْهَبَ الْخَلاَءَ وَقَامَتِ الصَّلاَةُ فَلْيَبْدَأْ بِالْخَلاَءِ  

We were in the company of 'Aishah. When her food was brought in, al-Qasim stood up to say his prayer. Thereupon , 'Aishah said : I heard the Messenger of Allaah (sal Allaahu alayhi wa sallam) say: Prayer should not be offered in presence of meals, nor at the moment when one is struggling with two evils (e.g. when one is feeling the call of nature.)  

كُنَّا عِنْدَ عَائِشَةَ فَجِيءَ بِطَعَامِهَا فَقَامَ الْقَاسِمُ يُصَلِّي فَقَالَتْ سَمِعْتُ رَسُولَ اللَّهِ ﷺ يَقُولُ لاَ يُصَلَّى بِحَضْرَةِ الطَّعَامِ وَلاَ وَهُوَ يُدَافِعُهُ الأَخْبَثَانِ  

The Messenger of Allah ﷺ said: Three things one is not allowed to do: supplicating Allah specifically for himself and ignoring others while leading people in prayer; if he did so, he deceived them; looking inside a house before taking permission: if he did so, it is as if he entered the house, saying prayer while one is feeling the call of nature until one eases oneself.  

قَالَ رَسُولُ اللَّهِ ﷺ ثَلاَثٌ لاَ يَحِلُّ لأَحَدٍ أَنْ يَفْعَلَهُنَّ لاَ يَؤُمُّ رَجُلٌ قَوْمًا فَيَخُصُّ نَفْسَهُ بِالدُّعَاءِ دُونَهُمْ فَإِنْ فَعَلَ فَقَدْ خَانَهُمْ وَلاَ يَنْظُرُ فِي قَعْرِ بَيْتٍ قَبْلَ أَنْ يَسْتَأْذِنَ فَإِنْ فَعَلَ فَقَدْ دَخَلَ وَلاَ يُصَلِّي وَهُوَ حَقِنٌ حَتَّى يَتَخَفَّفَ  

The Prophet ﷺ said: It is not permissible for a man who believes in Allah and in the Last Day that he should say the prayer while he is feeling the call of nature until he becomes light (by relieving himself). Then the narrator Thawr b. Yazid transmitted a similar tradition with the following wordings: "It is not permissible for a man who believes in Allah and in the Last Day that he should lead the people in prayer but with their permission; and that he should not supplicate to Allah exclusively for himself leaving all others. If he did so, he violated trust." Abu Dawud said: This is a tradition reported by the narrators of Syria; no other person has joined them in relating this tradition.  

عَنِ النَّبِيِّ ﷺ قَالَ لاَ يَحِلُّ لِرَجُلٍ يُؤْمِنُ بِاللَّهِ وَالْيَوْمِ الآخِرِ أَنْ يُصَلِّيَ وَهُوَ حَقِنٌ حَتَّى يَتَخَفَّفَ ثُمَّ سَاقَ نَحْوَهُ عَلَى هَذَا اللَّفْظِ قَالَ وَلاَ يَحِلُّ لِرَجُلٍ يُؤْمِنُ بِاللَّهِ وَالْيَوْمِ الآخِرِ أَنْ يَؤُمَّ قَوْمًا إِلاَّ بِإِذْنِهِمْ وَلاَ يَخْتَصَّ نَفْسَهُ بِدَعْوَةٍ دُونَهُمْ فَإِنْ فَعَلَ فَقَدْ خَانَهُمْ