Sheikh ul Islam and Mujaddid Muhammad bin Abdul-Wahhab may Allah have mercy on him said:
In the Name of God, Most Gracious, Most Merciful
Know that the Nullifiers of Islam are ten:
The First Nullifier; Shirk (associating partners) in the worship of Allah.
Allah Ta’ala says:
Verily, Allah does not forgive that partners be associated with Him in worship (i.e., Shirk), but He forgives what is less than that to whom He wills. [4:48 and 4:116]
And He Ta’ala says:
Verily, the one who mixes partners in worship with Allah (Shirk), then Paradise has been made forbidden for him and his final abode will be the Hellfire. And the wrongdoers will not have any helpers (in Hell). [5:72]
What falls into this is performing sacrifices to someone other than Allah, such as the person who offers a sacrifice to the Jinn or to a grave.
The Second Nullifier; Whoever places intermediaries between himself and Allah, calling unto them and asking intercession from them, and seeking reliance in them, has committed disbelief according to the Ijmaa (unanimous agreement).
The Third Nullifier; Whoever does not hold the polytheists to be disbelievers, or has doubts about their disbelief or considers their ways and beliefs to be correct, has committed disbelief.
The fourth Nullifier; Whoever believes that some guidance other than that of the Prophet’s peace be upon him is more complete than his guidance and that someone else’s judgement is better than his judgment, such as the one who prefers the judgement of the Tawaghith over his judgment, then he is a disbeliever.
The Fifth Nullifier; Whoever hates something that the Messenger of Allah peace be upon him came with, even though he may act on it, has disbelieved.
The Sixth Nullifier; Whoever mocks or ridicules any part of the Messenger’s Religion or its rewards or punishments has committed an act of disbelief. The proof for this is Allah’s statement:
Say: Was it Allah and His verses and His Messenger that you were mocking? Make no excuses, you have disbelieved after having had faith. [9:65-66]
The Seventh Nullifier; Sorcery, which includes magic spells that cause a person to hate something he seeks after (sarf) or love something he doesn’t seek after (‘atf). So whoever performs it or is pleased with it being done, has committed disbelief. The proof for this is Allah’s statement:
And neither of these two (angels) would teach anyone until they had first said to them: We are only a trial (for the people), so do not commit disbelief. [2:102]
The Eighth Nullifier; Supporting and assisting the polytheists against the Muslims. The proof for this is Allah’s statement:
And whoever amongst you takes them (i.e., the disbelievers) as allies and protectors then he is indeed from among them. Verily, Allah does not guide a wrong-doing people. [5:51]
The Ninth Nullifier; Whoever believes that it is permitted for some people to be free of (implementing) the Shari’ah of Muhammad (i.e., Islam), just as it was permitted for al-Khidr to be free from the Shari’ah of Mousa peace be upon him, then he is a disbeliever.
The Tenth Nullifier; Turning away from Allah’s Religion, not learning it or implementing it (is an act of disbelief). The proof for this is Allah’s saying:
And who does more wrong than he who is reminded of the ayat (signs/verses) of his Lord, then turns away from them. Verily, We shall extract retribution from the criminals. [32:22]
There is no difference, with regard to (committing any of) these nullifiers, between the one who jokes, the one who is serious or the one who does so out of fear. However, the one who commits them due to being coerced (is excused). We seek refuge in Allah from those things that bring about His Anger and painful Punishment. May the peace and blessing be on the best of His creatures, Muhammad.”
Detailed explanation books [PDF] :
نواقض اسلام – اسلام کے منافی امور (Urdu)