Riyad as-Salihin, Book 9, Hadith 1075 (In-Book) ⓘ

Ibn 'Umar (May Allah be pleased with them) reported: The Messenger of Allah said, "Islam is based on five (pillars): testifying that there is no true god except Allah and that Muhammad is His slave and Messenger; performing of Salat (Iqamat-as-Salat); the payment of Zakat; performing Hajj (pilgrimage) to the House [of Allah (Ka'bah)]; and Saum (fasting) during the month of Ramadan."[Al-Bukhari and Muslim].

وعن ابن عمر رضي الله عنهما قال‏:‏ قال رسول الله صلى الله عليه وسلم‏:‏ ‏ "‏ بني الإسلام على خمس‏:‏ شهادة أن لا إله إلا الله وأن محمدًا رسول الله، وإقام الصلاة، وإيتاء الزكاة، وحج البيت، وصوم رمضان‏" ‏ ‏(‏‏(‏متفق عليه‏)‏‏)‏‏.‏