Arkan-ul-Islaam are its basic foundations upon which it is established; they are five, mentioned in the narration by Ibn Umar radiyAllaahu `anhu in which the Prophet sallallaahu `alayhi wa sallam said:
“Islaam is raised on five (pillars): To establish His Tawheed [and in other narration “The Shahaadah (testimony) that Laa ilaaha illal-laah (none has the right to be worshipped but Allaah) and that Muhammad is Allaah’s slave and Messenger], establishment of prayers, payment of Zakaat, the fast of Ramadaan, and Pilgrimage (to Makkah). A person said (to the narrator) (which of the two precedes the other)-Pilgrimage or the fasts of Ramadaan? Upon this he (the narrator) replied: No (it is not the Pilgrimage first) but the fasts of Ramadaan precede the Pilgrimage, this is how I have heard it from Allaah’s Messenger.”
FIRST: The Shahaadah of:
Laa ilaaha illal-laah, Muhammad Rasoulullaah
It is the decisive belief expressed on the tongue as though one sees with his own eyes the certainty of his firm conviction. The fact that the Shahadah has been made as a single pillar despite the multiplicity in what is being attested is because of either of the following (reasons):
1 – The Messenger sallallaahu `alayhi wa sallam is a bearer (of news) about Allaah, the Exalted, attesting, therefore, that he sallallaahu `alayhi wa sallam is a true slave of Allaah and a bearer of the Message (of Islaam) is an integral part of the meaning of Shahaadah (Laa ilaaha illal-laah), or
2 – That the two testimonies Laa ilaaha illal-laah, and Muhammad Rasoulullaah, are the (required) bases for the rightness of deeds and of their acceptance, since both, the validity and acceptance of deeds, cannot be achieved without Ikhlass to Allaah (sincere devotion of intentions to Allaah alone) and Mutab`ah (following) of Rasoulullaah sallallaahu `alayhi wa sallam. It is through al-Ikhlass that the Shahaadah of Laa ilaaha illal-laah is realized, while through al-Mutaba`ah of Rassoulullaah, the Shahaadah that Muhammad is Allaah’s slave and Messengers is manifested.
Some of the benefits attained by the declaration of the great Shahaadah include the liberation of the heart and soul from slavery to the created, and from following paths other than the Messengers’ path.
SECOND: Regarding the Establishing of Prayers: it is worshipping Allaah by performing it in the right and perfect manner and on its prescribed times. Some of its benefits include the openness of the chest, contentment and joy, and restrainement from committing sins and wrongdoings.
THIRD: The Giving of Zakaat: is devoting worship to Allaah by offering the obligatory prescribed amount of charity deducted from the wealth upon which Zakaat is due. Some of its Benefits are: purifying the self from immoral characteristics like misery, and fulfilling the needs of Islaam and Muslims.
FOURTH: Fasting: it is devoting worship to Allaah by refraining from everything known to nullify the fast during the days of the month of Ramadaan. Fasting coaches the self to endure the relinquishment of what it likes seeking to gain the pleasure of Allaah.
FIFTH: The Hajj to The House of Allaah: is worshipping Allaah by going to the Sacred House (Al-Ka`bah) to execute the rites of Hajj.
Some of its benefits include: the training of the self to expend physical and financial sacrifices in obedience to Allaah ta `aalaa. This is the reason why Hajj is considered as one kind of Jihad in the cause of Allaah ta `aalaa.
The Benefits that we have mentioned above regarding the basics of Islaam, and others which we have not mentioned, makes of this Ummah a virtuous and purified Islamic Nation adhering to Allaah through the Deen of Truth, and treats the created with justice and truthfulness. This (conclusion) holds true because the right adherence to the rest of the Islamic Laws depends upon the proper practicability of the above basics.
The status of the Ummah will thrive and prosper as long as it properly adheres to the matters of its Deen. The degree of its prosperity that may escape by is proportional to the degree of abandonment of good adherence to matters of its Deen. Whoever seeks an evidence for this let him read the Saying of Allaah ta `aalaa:
And if the people of the towns had believed and had the Taqwa (piety, fear of Allaah), certainly, We should have opened for them the blessings from the heaven and the earth, but they belied (the Messengers). So We took them (with punishment) for what they used to earn (polytheism and crime, etc.). Did the people of the towns then feel secure against the coming of Our Punishment by night while they are asleep? Or, did the people of the towns then feel secure against the coming of Our Punishment in the forenoon while they play? Did they then feel secure against the Plan of Allaah. None feels secure from the Plan of Allaah except the people who are lost. (Qur’aan 7:96-99).
Let him also examine the history of those who preceded because history is a lesson for people of thought, and an insight for anyone free from any obstructing barrier to his heart. And it is Allaah alone whose Help can be sought.
 RadiyAllaahu `anhu (`anha, `anhuma, or `anhum), may Allaah be pleased with him (her, both or them), respectively.
 Agreed upon hadeeth: The text is that from Saheeh Muslim.
 As detailed by the Prophet Muhammad sallallaahu `alayhi wa sallam in his authentic Sunnah. See for example an excellent collection of the narrations describing the Prophet’s prayer in Shayekh Nassir-ud- Deen al-Albaanee’s book: “The Prophet’s Prayers”