TEN THINGS WHICH NULLIFY ONE'S ISLAM

Brother and Sister Muslim, you must be aware that there are matters which nullify your Islam. Please be Mindful of them :

1. Associating partners with Allah (shirk). Allah Most High says :
"Truly, whosoever sets up partners with Allah, then Allah has forbidden the Garden for him, and the Fire will be his abode. And for the wrongdoers there are no helpers." (Soorah Al-Ma'ida 5:72)
Calling upon the dead, asking their help, or offering them gifts or sacrifices are all forms of shirk.

2. Setting up intermediaries between oneself and Allah, making supplication to them, asking their intercession with Allah, and placing ones trust in them is unbelief (kufr).

3. Anyone who does not consider the polytheists (mushrikeen) to be unbelievers, or who has doubts concerning their unbelief, or considers their way to be correct, is himself/herself an unbeliever (kafir).

4. Anyone who believes any guidance to be more perfect, or a decision other than the Prophets decision to be better, is an unbeliever. This applies to those who prefer the rule of Evil (Taghout) to the Prophets rule. Some examples of this are:
(a) To believe that systems and laws made by human beings are better than the Shariah of Islam; for example,
That the Islamic system is not suitable for the twentieth century.
That Islam is the cause of the backwardness of the Muslims.
Or that al-Islam is a relationship between Allah and the Muslim. It should not interfere in other aspects of life.
(b)To say that enforcing the punishments prescribed Allah, such as cutting of the hand of the thief or the stoning of an adulterer, is not suitable for this day and age.
(c) To believe that it is permissible to give a rule from that which Allah did not reveal in Islamic transactions or matters of law, punishments or other affairs. Although one may not believe such things to be superior to the Shari'ah he in effect affirms such a stand by declaring a thing which Allah has totally prohibited, such as adultery, drinking alcohol or usury, to be permissible. According to the consensus of the Muslims, one who declares such things to be permissible is an unbeliever (Kafir)

5. Anyone who hates any part of what the Messenger of Allah [saw] has declared to be lawful has nullified his Islam, even though he may act in accordance with it. Allah Most High says :
"This is because they hate what Allah has sent down, so he has made their deeds fruitless" (Soorah Muhammad 47:9)

6. Anyone who ridicules any aspect of the religion of the Messenger of Allah [saw], or any of its rewards or punishments, becomes an unbeliever. Allah Most High says :
"Say: Was it Allah, and His signs and His Messenger that you were mocking? Make no excuse; you have disbelieved after you had believed." (Soorah At-Tawbah 9:65-66)

7. The practice of magic. Included in this, for example, is causing a rift between a husband and wife by turning his love for her into hatred, or tempting a person to do things he dislikes using black arts. One who engages in such a thing or is pleased with it is outside the fold of Islam. Allah Most High says :
" But neither of these two (angels, Harut and Marut) taught anyone (magic) till they had said, Indeed, we are a trial; then do not disbelieve. (Soorah Al-Baqarah 2:102)

8. Supporting and aiding polytheists against the Muslims. Allah Most High says :
"Whoever among you who takes them as allies is surely one of them. Truly, Allah does not guide the wrongdoers." (Soorah Al-Maida 5:51)

9. Anyone who believes that some people are permitted to deviate from the Shariah of Muhammad [saw] is an un believer by the word of Allah Most High :
"And whoever seeks a religion other than Islam, it will not be accepted of him, and in the hereafter he will be from among the losers." (Soorah al-Imran 3:85)

10. To turn completely away from the religion of Allah neither learning its precepts nor acting upon it. Allah most high says :
" And who does greater wrong than he who is reminded of the revelations of his Lord and turns aside therefrom Truly, We shall exact retribution from the guilty." (Soorah As-Sajdah 32:22)
and He [swt] also says (what means):
"But those who disbelieve turn away from that about which they are warned."

It makes no difference whether such violations are committed as a joke, in seriousness or out of fear, except when done under compulsion (i.e. from threat of loss of life )We seek refuge in Allah from such deeds as entail His wrath and severe punishment.

Source : http://ahmadjibril.com/articles/nullify.html