The Prophet ﷺ said: If anyone guards a believer from a hypocrite, Allah will send an angel who will guard his flesh on the Day of Resurrection from the fire of Jahannam; but if anyone attacks a Muslim saying something by which he wishes to disgrace him, he will be restrained by Allah on the bridge over Jahannam till he is acquitted of what he said.  

عَنِ النَّبِيِّ ﷺ قَالَ مَنْ حَمَى مُؤْمِنًا مِنْ مُنَافِقٍ أُرَاهُ قَالَ بَعَثَ اللَّهُ مَلَكًا يَحْمِي لَحْمَهُ يَوْمَ الْقِيَامَةِ مِنْ نَارِ جَهَنَّمَ وَمَنْ رَمَى مُسْلِمًا بِشَىْءٍ يُرِيدُ شَيْنَهُ بِهِ حَبَسَهُ اللَّهُ عَلَى جِسْرِ جَهَنَّمَ حَتَّى يَخْرُجَ مِمَّا قَالَ  

The Prophet ﷺ said: No (Muslim) man will desert a man who is a Muslim in a place where his respect may be violated and his honour aspersed without Allah deserting him in a place here he wishes his help; and no (Muslim) man who will help a Muslim in a place where his honour may be aspersed and his respect violated without Allah helping him in a place where he wishes his help. Yahya said: 'Ubaid Allah b. 'Abd Allah b. 'Umar and 'Uqbah b. Shaddad transmitted it to me. Abu Dawud said: This yahya b. Sulaim is the son of Zaid, the freed slave of the Prophet ﷺ, and Isma'il b. Bashir is the freed slave of Banu Maghalah. Sometimes the name of 'Utbah b. Shaddad is mentioned instead of 'Uqbah.  

قَالَ رَسُولُ اللَّهِ ﷺ مَا مِنِ امْرِئٍ يَخْذُلُ امْرَأً مُسْلِمًا فِي مَوْضِعٍ تُنْتَهَكُ فِيهِ حُرْمَتُهُ وَيُنْتَقَصُ فِيهِ مِنْ عِرْضِهِ إِلاَّ خَذَلَهُ اللَّهُ فِي مَوْطِنٍ يُحِبُّ فِيهِ نُصْرَتَهُ وَمَا مِنِ امْرِئٍ يَنْصُرُ مُسْلِمًا فِي مَوْضِعٍ يُنْتَقَصُ فِيهِ مِنْ عِرْضِهِ وَيُنْتَهَكُ فِيهِ مِنْ حُرْمَتِهِ إِلاَّ نَصَرَهُ اللَّهُ فِي مَوْطِنٍ يُحِبُّ نُصْرَتَهُ قَالَ يَحْيَى وَحَدَّثَنِيهِ عُبَيْدُ اللَّهِ بْنُ عَبْدِ اللَّهِ بْنِ عُمَرَ وَعُقْبَةُ بْنُ شَدَّادٍ