The Necessity of al-Fatihah and its Excellence

He would vehemently emphasise the importance of this surah, saying: "There is no prayer for the one who did not recite [in it] the opening chapter [at least]", and in another saying: That prayer is not sufficient in which a man does not recite the Opening of the Book. He also said: He who performs a prayer in which he does not recite the Opening of the Book, then it (i.e. the prayer) is deficient, it is deficient, it is deficient, incomplete.

He also said:

Allah the Blessed and Exalted has said: "I have divided the prayer between Myself and My servant, into two halves: half of it is for Me and half is for My servant, and My servant shall have what he has asked for."

Then the Messenger of Allah (sallAllahu 'alaihi wa sallam) said: Recite! The servant says "Praise be to Allah, the Lord of the Worlds"; Allah the Exalted says "My servant has praised Me". The servant says, "The Most Merciful, the Bestower of Mercy"; Allah says, "My servant has extolled Me". The servant says "Master of the Day of Judgment"; Allah the Exalted says, "My servant has glorified Me". The servant says, "It is You (Alone) we worship and it is You (Alone) we ask for help"; [He says:], "This is between Me and My servant, and My servant shall have what he has asked for". The servant says, "Guide us to the Straight Path, the Path of those whom You have favoured, not of those who receive Your anger, nor of those who go astray". [He says:], "All these are for My servant, and My servant shall have what he has asked for."

He also used to say: “Allah did not reveal in the Torah or the Gospel anything like the Mother of the Qur’an. It is the Seven Oft-Repeated [and the Grand Recitation which have been bestowed upon me].”

He (sallAllahu 'alaihi wa sallam) commanded "the one who prayed badly" to recite it in his prayer, but said to one who could not remember it, Say: “(I declare Allah free from all defects; all Praise be to Allah; none has the right to be worshipped but Allah; Allah is the Greatest; there is no might or power except by Allah).”

He also said to "the one who prayed badly": “If you know some of the Qur’an, then recite it, otherwise praise Allah, declare His Greatness and declare that none has the right to be worshipped but Allah.”