Is ritual prayer obligatory according to Divine sources?

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Ritual prayer is obligatory based on the Book (Quran), the Sunnah, and the Consensus (Ijma). The obligation is established by the Quranic verse stating: "And they were not commanded except to worship Allah, [being] sincere to Him in religion, inclining to truth, and to establish the prayer and give zakah. And that is the correct religion" (Quran 25:5). The Sunnah confirms this through the hadith narrated by Ibn 'Umar, where the Prophet, peace be upon him, stated: "Islam is built upon five: the testimony that there is no god but Allah and that Muhammad is the Messenger of Allah, establishing the prayer (Iqam as-Salat), giving zakah, fasting Ramadan, and performing the Hajj to the House for those who can find a way to it." This hadith is agreed upon (Muttafaq 'alayh).