The Book of Prayers - Sahih Muslim 394 a

He who does not recite Fatihat al-Kitab is not credited with having observed the prayer.

Commentary on the Hadith

This noble hadith establishes the fundamental obligation of reciting Surah al-Fatihah in every rak'ah of the obligatory prayer. The scholars of Islam are in consensus that the recitation of al-Fatihah is a pillar (rukn) of the prayer, without which the prayer is invalid.

The phrase "not credited with having observed the prayer" indicates the severe deficiency and nullification of the prayer when this essential component is omitted. This ruling applies to both the imam and the individual praying alone, according to the preponderant opinion of the jurists.

Al-Fatihah is uniquely termed "Umm al-Qur'an" (the Mother of the Qur'an) and "al-Sab' al-Mathani" (the Seven Oft-Repeated Verses) due to its comprehensive nature containing praise of Allah, affirmation of His Lordship, and supplication for guidance to the Straight Path.

The wisdom behind this obligation lies in the dialogue it establishes between the servant and his Lord, as mentioned in the qudsi hadith: "I have divided the prayer between Myself and My servant into two halves..." Thus, neglecting its recitation severs this spiritual communion.

Juridical Rulings

The Hanafi school differs slightly, considering it obligatory (wajib) rather than a pillar, but still essential for the validity of prayer according to the soundest opinion.

For one following an imam in audible prayers, the majority hold that listening attentively suffices in place of personal recitation, though some scholars recommend silent recitation during the imam's pauses.

If one forgets to recite al-Fatihah in a rak'ah, they must perform the prostration of forgetfulness (sujud al-sahw) to compensate for the omission, according to many scholars.