حَدَّثَنَا خَلاَّدُ بْنُ يَحْيَى، قَالَ: حَدَّثَنَا سُفْيَانُ، عَنْ يَزِيدَ بْنِ أَبِي زِيَادٍ، عَنْ عَمْرِو بْنِ سَلَمَةَ، عَنْ عَبْدِ اللهِ قَالَ: مَا مِنْ مُسْلِمَيْنِ إِلاَّ بَيْنَهُمَا مِنَ اللهِ عَزَّ وَجَلَّ سِتْرٌ، فَإِذَا قَالَ أَحَدُهُمَا لِصَاحِبِهِ كَلِمَةَ هَجْرٍ فَقَدْ خَرَقَ سِتْرَ اللهِ، وَإِذَا قَالَ أَحَدُهُمَا لِلْآخَرِ: أَنْتَ كَافِرٌ، فَقَدْ كَفَرَ أَحَدُهُمَا.
It is narrated from Sayyiduna Abdullah bin Mas'ud (may Allah be pleased with him), he said: There is a veil from Allah between every two Muslims. When one of them speaks abusively, he tears the veil of Allah. And when one of them says to the other, "You are a disbeliever," then one of them becomes a disbeliever.