Allaah's treatment of Muslims who disobey Him
2-3-2005 | IslamWeb
Question:
Allaah says that he punishes those who don't worship Him and don't do good deeds, and gives paradise to those who do good deeds. But where will those who are Muslims yet they don't act on its laws? Will Allaah forgive them or just put them in Fire?
Answer:
All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad 
is His slave and Messenger.
There are three categories of people in this regard.
The First Category: Those who enter Hellfire and will abide therein forever. These are the non-Muslims who are of different religions, and the hypocrites who show Islam and hide disbelief, like 'Abdullaah Ibn Ubay and the like. So whoever of these non-Muslims dies upon disbelief [or believing in any other religion than Islam] or as a hypocrite, then he enters Hellfire and abides therein forever.
The Second Category: Those who will not enter Hellfire at all, and these are the believers who have complete faith. Among them are the Prophets, the followers of the Prophets who were first and foremost to believe in them, the martyrs and whomever Allaah wishes not to admit into Hellfire, out of His Mercy and Grace even if these people deserve to enter Hellfire.
The Third Category: Those who will enter Hellfire and abide therein for a period of time and then they will be admitted to Paradise. These are the disobedient believers whom Allaah had wished to punish in Hellfire.
This is the belief and methodology of Ahlus-Sunnah Wal-Jamaa'ah.
Allaah says (what means): {Verily, Allaah forgives not that partners should be set up with him in worship, but He forgives except that (anything else) to whom He pleases, and whoever sets up partners with Allaah in worship, he has indeed invented a tremendous sin.} [Quran 4:48]
The Prophet said: "When the people of Paradise will enter Paradise and the people of Hell will go to Hell, Allaah will order those who have had faith equal to the weight of a grain of mustard seed to be taken out of Hell." [Al-Bukhari and Muslim]
Furthermore, the Prophet said: "Whoever amongst you fulfils his pledge, will be rewarded by Allaah, and whoever commits any of those sins and receives the legal punishment in this world for that sin, then that punishment will be an expiation for that sin, and whoever commits any of those sins and Allaah does not expose him, then his matter is in the Hands of Allaah, if He wishes He will punish him or if He wishes, He will forgive him." [Al-Bukhari and Muslim]
[The Prophet said the above narration when he sought the oath (Pledge of allegiance) from the Companions 
not to commit some forbidden acts and he mentioned six acts, and the Companions gave him the pledge for that].
For more benefit, please refer to Fataawa 85554 and 86740.
Allaah Knows best.