The Companions started the Book of Allah with Bismillah:
(1. In the Name of Allah, the Most Gracious, the Most Merciful.)
The scholars also agree that Bismillah is a part of an Ayah in Surat An-Naml (chapter 27). They disagree over whether it is a separate Ayah before every Surah, or if it is an Ayah, or a part of an Ayah, included in every Surah where the Bismillah appears in its beginning. Ad-Daraqutni also recorded a Hadith from Abu Hurayrah from the Prophet that supports this Hadith by Ibn Khuzaymah. Also, similar statements were attributed to `Ali, Ibn `Abbas and others.
The opinion that Bismillah is an Ayah of every Surah, except Al-Bara'ah (chapter 9), was attributed to (the Companions) Ibn `Abbas, Ibn `Umar, Ibn Az-Zubayr, Abu Hurayrah and `Ali. This opinion was also attributed to the Tabi`in: `Ata', Tawus, Sa`id bin Jubayr, Makhul and Az-Zuhri. This is also the view of `Abdullah bin Al-Mubarak, Ash-Shafi`i, Ahmad bin Hanbal, (in one report from him) Ishaq bin Rahwayh and Abu `Ubayd Al-Qasim bin Salam. On the other hand, Malik, Abu Hanifah and their followers said that Bismillah is not an Ayah in Al-Fatihah or any other Surah. Dawud said that it is a separate Ayah in the beginning of every Surah, not part of the Surah itself, and this opinion was also attributed to Ahmad bin Hanbal.
Muslim recorded that Abu Hurayrah said that the Prophet said,
(Whoever performs any prayer in which he did not read Umm Al-Qur'an, then his prayer is incomplete.) He said it thrice.
Abu Hurayrah was asked, “When we stand behind the Imam'' He said, "Read it to yourself, for I heard the Messenger of Allah say,
(Allah, the Exalted, said, `I have divided the prayer (Al-Fatihah) into two halves between Myself and My servant, and My servant shall have what he asks for.' If he says,
(All praise and thanks be to Allah, the Lord of existence.)
Allah says, `My servant has praised Me.' When the servant says,
(The Most Gracious, the Most Merciful.)
Allah says, `My servant has glorified Me.' When he says,
(The Owner of the Day of Recompense.) Allah says, `My servant has glorified Me,' or `My servant has related all matters to Me.' When he says,
(You (alone) we worship, and You (alone) we ask for help.) Allah says, `This is between Me and My servant, and My servant shall acquire what he sought.' When he says,
(Guide us to the straight path.The way of those on whom You have granted Your grace, not (the way) of those who earned Your anger, nor of those who went astray), Allah says, `This is for My servant, and My servant shall acquire what he asked for.').''
These are the words of An-Nasa'i, while both Muslim and An-Nasa'i collected the following wording, "A half of it is for Me and a half for My servant, and My servant shall acquire what he asked for.''
Muslim recorded that Abu Hurayrah said that the Prophet said,
(Whoever performs any prayer in which he did not read Umm Al-Qur'an, then his prayer is incomplete.) He said it thrice.
Abu Hurayrah was asked, “When we stand behind the Imam'' He said, "Read it to yourself, for I heard the Messenger of Allah say,
(Allah, the Exalted, said, `I have divided the prayer (Al-Fatihah) into two halves between Myself and My servant, and My servant shall have what he asks for.' If he says,
(All praise and thanks be to Allah, the Lord of existence.)
Allah says, `My servant has praised Me.' When the servant says,
(The Most Gracious, the Most Merciful.)
Allah says, `My servant has glorified Me.' When he says,
(The Owner of the Day of Recompense.) Allah says, `My servant has glorified Me,' or `My servant has related all matters to Me.' When he says,
(You (alone) we worship, and You (alone) we ask for help.) Allah says, `This is between Me and My servant, and My servant shall acquire what he sought.' When he says,
(Guide us to the straight path.The way of those on whom You have granted Your grace, not (the way) of those who earned Your anger, nor of those who went astray), Allah says, `This is for My servant, and My servant shall acquire what he asked for.').''
These are the words of An-Nasa'i, while both Muslim and An-Nasa'i collected the following wording, "A half of it is for Me and a half for My servant, and My servant shall acquire what he asked for.''
Muslim recorded that Abu Hurayrah said that the Prophet said,
(Whoever performs any prayer in which he did not read Umm Al-Qur'an, then his prayer is incomplete.) He said it thrice.
Abu Hurayrah was asked, “When we stand behind the Imam'' He said, "Read it to yourself, for I heard the Messenger of Allah say,
(Allah, the Exalted, said, `I have divided the prayer (Al-Fatihah) into two halves between Myself and My servant, and My servant shall have what he asks for.' If he says,
(All praise and thanks be to Allah, the Lord of existence.)
Allah says, `My servant has praised Me.' When the servant says,
(The Most Gracious, the Most Merciful.)
Allah says, `My servant has glorified Me.' When he says,
(The Owner of the Day of Recompense.) Allah says, `My servant has glorified Me,' or `My servant has related all matters to Me.' When he says,
(You (alone) we worship, and You (alone) we ask for help.) Allah says, `This is between Me and My servant, and My servant shall acquire what he sought.' When he says,
(Guide us to the straight path.The way of those on whom You have granted Your grace, not (the way) of those who earned Your anger, nor of those who went astray), Allah says, `This is for My servant, and My servant shall acquire what he asked for.').''
These are the words of An-Nasa'i, while both Muslim and An-Nasa'i collected the following wording, "A half of it is for Me and a half for My servant, and My servant shall acquire what he asked for.''
Muslim recorded that Abu Hurayrah said that the Prophet said,
(Whoever performs any prayer in which he did not read Umm Al-Qur'an, then his prayer is incomplete.) He said it thrice.
Abu Hurayrah was asked, “When we stand behind the Imam'' He said, "Read it to yourself, for I heard the Messenger of Allah say,
(Allah, the Exalted, said, `I have divided the prayer (Al-Fatihah) into two halves between Myself and My servant, and My servant shall have what he asks for.' If he says,
(All praise and thanks be to Allah, the Lord of existence.)
Allah says, `My servant has praised Me.' When the servant says,
(The Most Gracious, the Most Merciful.)
Allah says, `My servant has glorified Me.' When he says,
(The Owner of the Day of Recompense.) Allah says, `My servant has glorified Me,' or `My servant has related all matters to Me.' When he says,
(You (alone) we worship, and You (alone) we ask for help.) Allah says, `This is between Me and My servant, and My servant shall acquire what he sought.' When he says,
(Guide us to the straight path.The way of those on whom You have granted Your grace, not (the way) of those who earned Your anger, nor of those who went astray), Allah says, `This is for My servant, and My servant shall acquire what he asked for.').''
These are the words of An-Nasa'i, while both Muslim and An-Nasa'i collected the following wording, "A half of it is for Me and a half for My servant, and My servant shall acquire what he asked for.''
Muslim recorded that Abu Hurayrah said that the Prophet said,
(Whoever performs any prayer in which he did not read Umm Al-Qur'an, then his prayer is incomplete.) He said it thrice.
Abu Hurayrah was asked, “When we stand behind the Imam'' He said, "Read it to yourself, for I heard the Messenger of Allah say,
(Allah, the Exalted, said, `I have divided the prayer (Al-Fatihah) into two halves between Myself and My servant, and My servant shall have what he asks for.' If he says,
(All praise and thanks be to Allah, the Lord of existence.)
Allah says, `My servant has praised Me.' When the servant says,
(The Most Gracious, the Most Merciful.)
Allah says, `My servant has glorified Me.' When he says,
(The Owner of the Day of Recompense.) Allah says, `My servant has glorified Me,' or `My servant has related all matters to Me.' When he says,
(You (alone) we worship, and You (alone) we ask for help.) Allah says, `This is between Me and My servant, and My servant shall acquire what he sought.' When he says,
(Guide us to the straight path.The way of those on whom You have granted Your grace, not (the way) of those who earned Your anger, nor of those who went astray), Allah says, `This is for My servant, and My servant shall acquire what he asked for.').''
These are the words of An-Nasa'i, while both Muslim and An-Nasa'i collected the following wording, "A half of it is for Me and a half for My servant, and My servant shall acquire what he asked for.''
Muslim recorded that Abu Hurayrah said that the Prophet said,
(Whoever performs any prayer in which he did not read Umm Al-Qur'an, then his prayer is incomplete.) He said it thrice.
Abu Hurayrah was asked, “When we stand behind the Imam'' He said, "Read it to yourself, for I heard the Messenger of Allah say,
(Allah, the Exalted, said, `I have divided the prayer (Al-Fatihah) into two halves between Myself and My servant, and My servant shall have what he asks for.' If he says,
(All praise and thanks be to Allah, the Lord of existence.)
Allah says, `My servant has praised Me.' When the servant says,
(The Most Gracious, the Most Merciful.)
Allah says, `My servant has glorified Me.' When he says,
(The Owner of the Day of Recompense.) Allah says, `My servant has glorified Me,' or `My servant has related all matters to Me.' When he says,
(You (alone) we worship, and You (alone) we ask for help.) Allah says, `This is between Me and My servant, and My servant shall acquire what he sought.' When he says,
(Guide us to the straight path.The way of those on whom You have granted Your grace, not (the way) of those who earned Your anger, nor of those who went astray), Allah says, `This is for My servant, and My servant shall acquire what he asked for.').''
These are the words of An-Nasa'i, while both Muslim and An-Nasa'i collected the following wording, "A half of it is for Me and a half for My servant, and My servant shall acquire what he asked for.''