CALLING KAFIR IN ISLAM
What Quran says about Mocking, Ridiculing, Calling Kafir or Killing Muslims
[49:11]"O you who believe, let not a folk ridicule another folk who may be better than they are; nor should women ridicule other women who may be better than them. Neither defame one another nor insult one another by calling names. That is the name of lewdness after faith and who so turns not in repentance, such are evildoers."
[49:12] "O ye who believe! Avoid such suspicion for verily suspicion is a sin and spy not and some of you backbite the other; What! Likest one of you eat the flesh of his dead brother."
He, who calls a Muslim a Kaffir, becomes a Kaffir himself!
Book 001, Number 0116:
It is reported on the authority of Ibn 'Umar that the Apostle (may peace and blessings be upon him) observed: When a man calls his brother an unbeliever, it returns (at least) to one of them.
Book 001, Number 0117:
It is reported on the authority of Ibn 'Umar that the Messenger of Allah (may peace and blessings be upon him) said: Any person who called his brother: or unbeliever (has in fact done an act by which this unbelief) would return to one of them. If it were so, as he asserted (then the unbelief of man was confirmed but if it was not true), then it returned to him (to the man who labeled it on his brother Muslim).
The commentator Of Sahih Muslim states:
This hadith tells us that labelling others with unbelief is not an insignificant thing but a matter of serious import, and one should use utmost care in passing these remarks on others. This hadith also shows that whatever is said or done in the world is retained and preserved and nothing lost. This point has been illustrated by a hadith recorded in Abu Dawud and narrated on the authority of Darda. The Holy Prophet observed: "When a person curses anyone, it goes directly towards the sky, but when it finds no path to Mercy, it comes down, then moves right and left but finding no place moves towards the man who was cursed, but if he does not deserve it, then it comes back to the one who has cursed the other one.
Ref:
The condition of the faith of one who calls his brother Muslim an unbeliever: Kitab al-Iman (the book of faith). Sahih Muslim, p41, chapter number XXVII
1. To believe in the unseen (as we believe in the Creator and the Hereafter without seeing them).
2. To offer the five daily prayers.
3. To spend, in the way of God, a portion of the wealth God had provided us (by paying Zakat).
4. To believe in that which God has revealed to His Messenger Muhammad PBUH&HP.
5. To believe in that which was revealed to all Messengers before Muhammad.
6. To believe in the Hereafter.
Thus, whoever meets these six requirements, as indicated by the first verse, will be righteous, and as indicated by the last verse, will be well-guided and successful.
THIS IS THE CORE BELIEF OF SHIAS TOO.
[Burg 85:10] Those who persecute (or draw into temptation) the Believers, men
and women, and do not turn in repentance, will have the Penalty of Hell: They
will have the Penalty of the Burning Fire.
"O ye who believe ! take not the Jews and the Christians for friends. They are
friends of each other. And whose among you takes them for friends is indeed one
of them. Verily ALLAH guides not the unjust people. (Al-Maidah : 51)"
"ALLAH has set a seal on their hearts and their ears, and over their eyes is a
covering; and for them is a grievous chastisement. (Al-Baqrah : 7) "
"O you who believe, if a transgressor brings to you news, verify it, lest you inflict damage on people unwittingly; you may consequently regret your hasty action." (Ch. 49, v.6)
Those people who declare other muslims as kaffirs are serving the enemies of Islam only.
May Allah's curse be on those who strive to cause fitna amongst the muslims and may Allah guide those who are misguided by these mischief makers.