Ibn 'Umar (May Allah be pleased with them) reported

The Messenger of Allah (ﷺ) said, "(The superstructure of) Islam is based on five (pillars), testifying the fact that La ilaha illallah wa anna Muhammad -ar-Rasul-ullah [there is no true god except Allah, and Muhammad ((ﷺ)) is the Messenger of Allah], establishing As- Salat (the prayers), paying Zakat (poor due), the pilgrimage to the House [of Allah (Ka'bah)], and the Saum (fasting) during the month of Ramadan."

[Al-Bukhari and Muslim].