Sayyidina Ibn Umar (RA) reported that Allah’s Messenger (SAW) said, “Islam is in five things: the testimony that there is no God but Allah and that Muhammad is Allah’s Messenger, the establishment of salah, the payment of zakah, the fast of Ramadan and Hajj of the House (of Allah).
[Ahmed 6309, Bukhari 8, Muslim 16, Nisai 5011]