Narrated Ibn `Umar: Allah’s Apostle said: Islam is based on
(the following) five (principles): ?

1. To testify that there
is no deity (owing the right to be worshipped) but Allah and
that Muhammad is Allah’s Messenger. ?2. To offer the
(compulsory congregational) prayers dutifully and perfectly.
?3. To pay Zakat (i.e. obligatory charity) . ?4. To perform
Hajj. (i.e. Pilgrimage to Mecca) ?5. To observe fast during
the month of Ramadan.

(Bukhari Shareef)