Fundamentals of Islamic Doctrine

It is well known from the sound evidence in the Book and the Sunnah that sayings and deeds are not accepted unless originate from a true doctrine. So if the doctrine is not sound then all what originates will be nullified for Allah said, "If any one rejects faith, fruitless is his work, and in the Hereafter he will be in the ranks of those who have lost (all spiritual good)."

1. First, the Belief in Allah: The belief in Allah necessitates the belief that He is the only worthy god being worshipped for being the only Creator, Cherisher, and Provider of the creation. It is He Who can reward their pious and punish their rebellious. In fact, it is this purpose for which He created the Worlds, He said, "I have only created Jinn and men, that they may serve Me. No Sustenance do I require of them, nor do I require that they should feed Me. For Allah is He Who gives (all) Sustenance, - Lord of Power - steadfast (forever)."
   
2. Second, the belief in Angels: This includes the belief in them specifically and as a whole. So Muslim has to believe that there exists Angels whom Allah created and molded them to obey. They are of many types, some of them are assigned to hold the Throne (of Allah), others are treasurers for Paradise and Hell, others are assigned to record people’s deeds. And we believe in those whom Allah named such as Jibril (Gabriel), MiKa’el (Michael), Malek the treasurer of Hell, and Israfil the one who will blow the Sur (Trumpet). ‘Aishah narrated that the Prophet said, “Angels have been created (by Allah) from light, and jinn have been created (by Allah) from fire without smoke, and Adam has been created (by Allah) from what was described for you (dust)."
   
3. Third, the belief in Books: It should be generally believed that Allah has descended Noble Books unto His Prophets and Messengers to clarify His Right on people and invoke it. We believe specifically in those which Allah named like the Tawrat (Torah), the Injil (Gospel), the Zabur (Psalms), and the Qua’an. In fact, Qur'an is the Last and the Best of them, and it is the Book which overwhelmed and confirmed what had preceded. Moreover, it is the Book to which the entire nation has to resort in judgement in addition to the sound Sunnah reported, Allah said, "To you We sent the Scripture in truth, confirming the Scripture that came before it, and guarding it in safety."
   
4. Fourth, the belief in the Messengers: A Muslim has to believe in Messengers specifically and as a whole. So we believe that Allah has sent to His servants warning and bearing good tidings Messengers invoking what is Truth. Consequently, he who followed their Message has won happiness, and he who left them out shall feel regret and be disappointed. Their last and best one is our Prophet Muhammad. Allah said, "For We assuredly sent amongst every People a messenger, (with the Command), "Serve Allah and eschew Evil}." And He said, "Muhammad is not the father of any of your men, but (he is) the Messenger of Allah, and the Seal of the Prophets" And we believe in whom Allah named like Nuh (Noah), Hud, Saleh, Ibrahim (Abraham), Musa (Moses), Isa (Jesus), and others may Allah bless them all.
   
5. Fifth, the belief in the Last Day (Day of Resurrection):This includes the belief in what Allah has revealed and what His Messenger has informed about. These are things that shall happen after death like the grave trial and torture and ease, the Sirat (Path over Hell), Mizan (Balance of deeds), Account, Reward, and distributing books of deeds. This includes the aimed basin of the Prophet Muhammad, seeing and speaking with Allah which are gifted only to believers.
   
6. Sixth, the belief in Allah’s Decree and Predestination: It is the strict dogma that Allah has created and owned everything, and that He has preordained the destiny of everything: guidance and going astray, and that everything is under His Control. As for the belief in Allah’s Preordainment, it is done according to Allah’s Knowledge which has preceded and what His Wisdom necessitates. It includes the following: Knowledge, Writing down, Will, Creating.

In fact, this is shown in Allah’s Book and in His Messenger’s Sunnah.
In Allah’s Book, He says, “TawhidIt is not righteousness that you turn your faces towards East or West; but it is righteousness to believe in Allah and the Last Day, and the Angels, and the Book, and the Messengers”, and concerning the Qadar (Destiny), He says,"TawhidVerily, all things have We created in proportion and measure. And Our Command is but a single (Act), like the twinkling of an eye."

Omar bin Al-Khattab narrated, ‘One day we were sitting in the company of Allah's Messenger when there appeared before us a man dressed in pure white clothes, his hair extraordinarily black. There were no signs of travel on him. None amongst us recognized him. At last, he sat with the Messenger. He knelt before him placed his palms on his thighs and said, ‘O Muhammad r, inform me about Islam’. The Messenger of Allah r said, “Al-Islam implies that you testify ‘Lâ ilâha illAllah’ (None has the right to be worshipped but Allah), and you establish Salat (Prayer), pay Zakat, observe the fast of Ramadan, and perform Hajj (Pilgrimage) to the (House of Allah), if you are solvent enough (to bear the expense of) the journey”. He (the inquirer) said, ‘You have told the truth’. He (Umar ibn al-Khattab) said, ‘It amazed us that he would put the question and then he would himself verify the truth’. He (the inquirer) said, ‘Inform me about Iman (Faith)’. He (the Prophet) replied, “That you affirm your faith in Allah, in His angels, in His Books, in His Messengers, in the Day of Judgment, and you affirm your faith in the Divine Decree about good and evil”. He (the inquirer) said, ‘You have told the truth’. He (the inquirer) again said, ‘Inform me about al-Ihsan (performance of good deeds)’. He (the Noble Prophet) said, “That you worship Allah as if you are seeing Him, for though you don't see Him, He, verily, sees you”.  He (the inquirer) again said, ‘Inform me about the hour (of the Doom)’. He (the Prophet) remarked, “One who is asked knows no more than the one who is inquiring (about it)”. He (the inquirer) said, ‘Tell me some of its indications’. He (the Holy Prophet) said, “That the slave-girl will give birth to her mistress and master, that you will find barefooted, destitute goat-herds vying with one another in the construction of magnificent buildings”. He (the narrator, Umar ibn al-Khattab) said, ‘Then he (the inquirer) went on his way but I stayed with him (the Noble Prophet) for a long while. He then, said to me, “Omar, do you know who this inquirer was?” I replied, ‘Allah and His Messenger know best’. He (the Noble Prophet) remarked, “He was Jibril (Gabriel, the Angel). He came to you in order to instruct you in matters of your religion”.

As a matter of fact, these pillars are set into full agreement amongst Messengers and Divine Laws. Holy Books have been descended to assure, and none of the mankind is considered faithful except after believing in them, and whoever denies one of them is kept out of faith into unfaith.