وَحَدَّثَنَاهُ إِسْحَاقُ بْنُ إِبْرَاهِيمَ الْحَنْظَلِيُّ، أَخْبَرَنَا سُفْيَانُ بْنُ عُيَيْنَةَ، عَنِ الْعَلاَءِ، عَنْ أَبِيهِ، عَنْ أَبِي هُرَيْرَةَ، عَنِ النَّبِيِّ صلى الله عليه وسلم قَالَ ‏"‏ مَنْ صَلَّى صَلاَةً لَمْ يَقْرَأْ فِيهَا بِأُمِّ الْقُرْآنِ فَهْىَ خِدَاجٌ - ثَلاَثًا - غَيْرُ تَمَامٍ ‏"‏ ‏.‏ فَقِيلَ لأَبِي هُرَيْرَةَ إِنَّا نَكُونُ وَرَاءَ الإِمَامِ ‏.‏ فَقَالَ اقْرَأْ بِهَا فِي نَفْسِكَ فَإِنِّي سَمِعْتُ رَسُولَ اللَّهِ صلى الله عليه وسلم يَقُولُ ‏"‏ قَالَ اللَّهُ تَعَالَى قَسَمْتُ الصَّلاَةَ بَيْنِي وَبَيْنَ عَبْدِي نِصْفَيْنِ وَلِعَبْدِي مَا سَأَلَ فَإِذَا قَالَ الْعَبْدُ ‏ Begin hadith 8‏ ‏.‏ قَالَ اللَّهُ تَعَالَى حَمِدَنِي عَبْدِي وَإِذَا قَالَ ‏ Begin hadith 7‏ ‏.‏ قَالَ اللَّهُ تَعَالَى أَثْنَى عَلَىَّ عَبْدِي ‏.‏ وَإِذَا قَالَ ‏ Begin hadith 6‏ ‏.‏ قَالَ مَجَّدَنِي عَبْدِي - وَقَالَ مَرَّةً فَوَّضَ إِلَىَّ عَبْدِي - فَإِذَا قَالَ ‏ Begin hadith 5‏ ‏.‏ قَالَ هَذَا بَيْنِي وَبَيْنَ عَبْدِي وَلِعَبْدِي مَا سَأَلَ ‏.‏ فَإِذَا قَالَ ‏ Begin hadith 4‏ ‏.‏ قَالَ هَذَا لِعَبْدِي وَلِعَبْدِي مَا سَأَلَ ‏"‏ ‏.‏ قَالَ سُفْيَانُ حَدَّثَنِي بِهِ الْعَلاَءُ بْنُ عَبْدِ الرَّحْمَنِ بْنِ يَعْقُوبَ دَخَلْتُ عَلَيْهِ وَهُوَ مَرِيضٌ فِي بَيْتِهِ فَسَأَلْتُهُ أَنَا عَنْهُ ‏.‏

Abu Huraira reported: The Apostle of Allah (PBUH) said: If anyone observes prayer in which he does not recite Umm al-Qur'an, It is deficient [he said this three times] and not complete. It was said to Abu Huraira: At times we are behind the Imam. He said: Recite it inwardly, for he had heard the Messenger of Allah (PBUH) declare that Allah the Exalted had said: I have divided the prayer into two halves between Me and My servant, and My servant will receive what he asks. When the servant says: Praise be to Allah, the Lord of the universe, Allah the Most High says: My servant has praised Me. And when he (the servant) says: The Most Compassionate, the Merciful, Allah the Most High says: My servant has lauded Me. And when he (the servant) says: Master of the Day of judg- ment, He remarks: My servant has glorified Me. and sometimes He would say: My servant entrusted (his affairs) to Me. And when he (the worshipper) says: Thee do we worship and of Thee do we ask help, He (Allah) says: This is between Me and My servant, and My servant will receive what he asks for. Then, when he (the worshipper) says: Guide us to the straight path, the path of those to whom Thou hast been Gracious not of those who have incurred Thy displeasure, nor of those who have gone astray, He (Allah) says: This is for My servant, and My servant will receive what he asks for. Sufyan said: 'Ala b. 'Abd al-Rahman b. Ya'qub narrated it to me when I went to him and he was confined to his home on account of illness, and I asked him about it. Translation Not Available

Book reference: Sahih Muslim Book 4 Hadith 775
Web reference: Sahih Muslim Book 4 Hadith 395 a