If the testimony of an acknowledger of the sins is not accepted...
If the testimony of an acknowledger of the sins is not accepted, nothing will be accepted except testimony of the Prophets -as and the successors -asws , may the Salawaat of Allah -azwj be upon them -asws , because they -asws are the infallible besides rest of the people.
فَمَنْ لَمْ تَرَهُ بِعَيْنِكَ يَرْتَكِبُ ذَنْباً أَوْ لَمْ يَشْهَدْ عَلَيْهِ بِذَلِكَ شَاهِدَانِ فَهُوَ مِنْ أَهْلِ الْعَدَالَةِ وَ السَّتْرِ- وَ شَهَادَتُهُ مَقْبُولَةٌ وَ إِنْ كَانَ فِي نَفْسِهِ مُذْنِباً وَ مَنِ اغْتَابَهُ بِمَا فِيهِ فَهُوَ خَارِجٌ عَنْ وَلَايَةِ اللَّهِ عَزَّ وَ جَلَّ دَاخِلٌ فِي وَلَايَةِ الشَّيْطَانِ The one whom you have not seen with your own eyes indulging in a sin, or two witnesses have not testified upon him with that, so he is from the ones righteous of the justice and the covering up, and his testimony is acceptable, and even if he was a sinner within himself, and the one who backbites him, he is outside from the Wilayah of Allah -azwj Mighty and Majestic and inside the wilayah of Satan -la .
And my -asws father -asws had narrated to me -asws from his -asws father, from his -asws forefathers that Rasool-Allah -saww said: ‘One who backbites a Momin with what is in him, Allah -azwj will not Gather between the two in the Paradise, ever! And the one who backbites a Momin with what isn’t in him, the protection between them is cut off, and the backbiter would be in the Fire, being eternally in it, and evil is the destination’’.
[13] Defender of a Muslim is in Paradise: ثواب الأعمال أَبِي عَنْ عَلِيٍّ عَنْ أَبِيهِ عَنِ النَّوْفَلِيِّ عَنِ السَّكُونِيِّ عَنْ أَبِي عَبْدِ اللَّهِ ع قَالَ قَالَ رَسُولُ اللَّهِ ص مَنْ رَدَّ عَنْ عِرْضِ أَخِيهِ الْمُسْلِمِ وَجَبَتْ لَهُ الْجَنَّةُ الْبَتَّةَ.
(The book) ‘Sawaab Al Amaal’ – My father, from Ali, from his father, from Al Nowfaly, from Al Sakuny, ‘From Abu Abdullah -asws having said: ‘Rasool-Allah -saww said: ‘One who defends an honour of his Muslim brother, the Paradise is obligated for him indeed’’.