Islam is based on five pillars which the Messenger (‎‎ﷺ) has explained for us. The Prophet said: “Islam is built upon five [pillars]: the testimony that there is no god but Allah and that Muhammad is the Messenger of Allah; establishing regular prayer (salah); paying the zakah; Hajj (pilgrimage) and fasting Ramadan.”

(al-Bukhaari, no. 8)