Quran 49: 11-12, which mean:
(11. O you who believe, no men shall ridicule other men, for they may be better than they [will be in the Next Life]. Nor shall any women ridicule other women, for they may be better than they [will be in the Next Life.]
Nor shall you mock one another, nor revile one another by nicknames a. [The one who acts like this is an "ungodly".]
An evil name is the "ungodliness" after the "belief". b
Anyone who does not repent [from this act], such are the wrong-doers c.
12. O you who believe, avoid most of [bad] suspicion [about believers], for surely suspicion in some cases is a sin [of the suspicious one],
and do not spy d,
nor let some of you backbite others e;
Does anyone of you like to eat the flesh of his dead [: absent] brother? f
But you abhor it g;
And avoid God's [punishment for the backbiting], surely God is All-Accepting the repentance [of those who repent], Most-Merciful [to those who regret.])
................................................................................................................................................................................................................................................................................
11 a The meaning: Let not anyone of you call another with some nickname which he dislikes.
11 b It means: It will be an evil title to be called an "ungodly" after being called a "believer"; i.e. after you were believers, you will become ‘ungodly’ because of such bad manners.
11 c i.e. they wrong people with their hurtful words.
12 d i.e. do not seek after the flaws and defects of Muslims; because anyone who seeks after the flaws and defects of Muslims to expose them, God will expose him even in his family.
12 e i.e. do not mention anyone of you, when he is absent, with something he dislikes.
12 f i.e. like the wolf; i.e. do not be like wolves which eat the flesh of each other; because the backbiting leads to enmity so that they will be like wolves; this actually is a parable said about the backbiting.
It means: when his brother is absent.
And it is narrated from Jabir, one of the companions of Prophet Mohammed, that the messenger of God said: "Avoid the backbiting for it is worse than the adultery; because the adulterer may repent and God may accept his repentance, while the backbiter will not be forgiven unless the one, whom he backbites, will pardon him."
12 g It means: as do you abhor the eating of your dead brother's flesh, then you should avoid the backbiting.
http://quran-ayat.com/pret/49.htm#a49_11
(11. O you who believe, no men shall ridicule other men, for they may be better than they [will be in the Next Life]. Nor shall any women ridicule other women, for they may be better than they [will be in the Next Life.]
Nor shall you mock one another, nor revile one another by nicknames a. [The one who acts like this is an "ungodly".]
An evil name is the "ungodliness" after the "belief". b
Anyone who does not repent [from this act], such are the wrong-doers c.
12. O you who believe, avoid most of [bad] suspicion [about believers], for surely suspicion in some cases is a sin [of the suspicious one],
and do not spy d,
nor let some of you backbite others e;
Does anyone of you like to eat the flesh of his dead [: absent] brother? f
But you abhor it g;
And avoid God's [punishment for the backbiting], surely God is All-Accepting the repentance [of those who repent], Most-Merciful [to those who regret.])
................................................................................................................................................................................................................................................................................
11 a The meaning: Let not anyone of you call another with some nickname which he dislikes.
11 b It means: It will be an evil title to be called an "ungodly" after being called a "believer"; i.e. after you were believers, you will become ‘ungodly’ because of such bad manners.
11 c i.e. they wrong people with their hurtful words.
12 d i.e. do not seek after the flaws and defects of Muslims; because anyone who seeks after the flaws and defects of Muslims to expose them, God will expose him even in his family.
12 e i.e. do not mention anyone of you, when he is absent, with something he dislikes.
12 f i.e. like the wolf; i.e. do not be like wolves which eat the flesh of each other; because the backbiting leads to enmity so that they will be like wolves; this actually is a parable said about the backbiting.
It means: when his brother is absent.
And it is narrated from Jabir, one of the companions of Prophet Mohammed, that the messenger of God said: "Avoid the backbiting for it is worse than the adultery; because the adulterer may repent and God may accept his repentance, while the backbiter will not be forgiven unless the one, whom he backbites, will pardon him."
12 g It means: as do you abhor the eating of your dead brother's flesh, then you should avoid the backbiting.
http://quran-ayat.com/pret/49.htm#a49_11