The Pillars of Islam
It is narrated on the authority of ‘Abdullah son of Umar (may Allah be pleased with them) that the Messenger of Allah (may peace of Allah be upon him) said:
“Al-Islam is raised on five (pillars),
the oneness of Allah, (Testifying that there is no god except Allah and that Muhammad is the (final) Messenger of Allah);
the establishment of prayer, (To perform the (obligatory five daily) prayers with tranquility, awareness and full-concentration);
payment of zakat, (If the Muslims own 85 grams of gold or that which is equivalent in terms of money, then he is required to extract 2.5% of this value once a year of ownership has passed. As for other items, then the rates differ accordingly);
the fast of Ramadan, (To refrain from food and drink and sexual intercourse and all other specified things from the time of Fajr until the time of Maghrib);
the Pilgrimage to Makkah, (for whoever is physically and financially able to do so).
A person said (to ‘Abdullah b. Umar the narrator): “Which of the two precedes the other-Pilgrimage or the fasts of Ramadan?”
Upon this he (the narrator) replied: “No (it is not the Pilgrimage first) but the fasts of Ramadan precede the Pilgrimage.”“
[Sahih Muslim, Book #001, Hadith #0018]