The Messenger of Allah ﷺ said, "Islam is built upon five things: the testimony that there is no god but Allah and that Muhammad is the Messenger of Allah, establishing the prayer, giving the zakat, the pilgrimage, and fasting Ramadan."
قال رسول الله ﷺ: بني الإسلام على خمس: شهادة أن لا إله إلا الله، وأن محمدا رسول الله، وإقام الصلاة، وإيتاء الزكاة، والحج، وصوم رمضان.
Bukhari narrated it in the Book of Faith (8), and Muslim in the Book of Faith (16:22), both through Hanzala bin Abu Sufyan, who said, "I heard Ikrima bin Khalid narrate from Ibn Umar," and he related it. The wording given here is Bukhari's.