サヒーフ・ムスリム #1

بُنِيَ الإِسْلاَمُ عَلَى خَمْسٍ شَهَادَةِ أَنْ لاَ إِلَهَ إِلاَّ اللَّهُ وَأَنَّ مُحَمَّدًا رَسُولُ اللَّهِ وَإِقَامِ الصَّلاَةِ وَإِيتَاءِ الزَّكَاةِ وَالْحَجِّ وَصَوْمِ رَمَضَانَ

The Messenger of Allah (ﷺ) said: 'Islam is based on five (pillars): testifying that there is no god but Allah and that Muhammad is the Messenger of Allah, establishing prayer, paying zakat, fasting Ramadan, and performing Hajj to the House if one is able.'