Allah the Exalted and Most Honored said,
[وَاتَّقُواْ 
اللَّهَ]
(And have Taqwa of Allah), that is, regarding what He has commanded you and 
forbidden for you. Fear Him and beware of Him,
[إِنَّ اللَّهَ 
تَوَّابٌ رَّحِيمٌ]
(Verily, Allah is the One Who forgives and accepts repentance, Most 
Merciful.) He forgives those who repent to Him, is merciful with those who go 
back to Him and trust in Him. The majority of scholars have stated that 
repentance for committing the sin of backbiting is that one refrains from 
backbiting intending not to repeat it again. There is a difference of opinion if 
whether feeling remorse is required in this case, and also if one should 
apologize to those who he has backbitten. Some scholars stated that it is not 
necessary for one to ask those whom he has backbitten to forgive him, because if 
they knew what was said about them, they could be hurt more than if they were 
not told about it. It is better, they said, that one should praise those whom he 
has backbitten in audiences in which he has committed the act. It is also better 
if one defends the injured party against any further backbiting, as much as one 
can, as recompense for his earlier backbiting.
[يأَيُّهَا النَّاسُ 
إِنَّا خَلَقْنَـكُم مِّن ذَكَرٍ وَأُنْثَى وَجَعَلْنَـكُمْ شُعُوباً وَقَبَآئِلَ 
لِتَعَـرَفُواْ إِنَّ أَكْرَمَكُمْ عَندَ اللَّهِ أَتْقَـكُمْ إِنَّ اللَّهَ 
عَلِيمٌ خَبِيرٌ ]
(13. O mankind! We have created you from a male and a female, and made you 
into nations and tribes that you may know one another. Verily, the most 
honorable of you with Allah is that (believer) who has At-Taqwa. Verily, Allah 
is All-Knowing, All-Aware.)