Caution: Translations of Quran and Ḥadīth may lead to possible misapplications and misinterpretations. This site is intended for students of sacred knowledge that are proficient in comprehending classical Arabic and have a strong foundation in Islamic sciences. Also note that religious injunctions rely on several aspects beyond what one may glean through reading individual aḥādīth.
bayhaqi:2726Abū al-Fatḥ Muḥammad b. Aḥmad b. Abū al-Fawāris al-Ḥāfiẓ> Abū ʿAlī b. al-Ṣawwāf > Abū ʿAlī Bishr b. Mūsá > Abū Zakariyyā Yaḥyá b. Isḥāq > Mahdī b. Maymūn > Wāṣil al-Aḥdab > Abū Wāʾil > Ḥudhayfah

[Machine] He came across a man who was praying but was not completing the bowing and prostrations. So he asked him, "How long have you been praying like this?" The man replied, "For forty years, or maybe it was such and such time." He said to him, "You have not prayed to God a prayer since such and such time." He said, "Mahdi (the guided one) and I believe he said, "If you were to die, you would die upon other than the Sunnah of Muhammad ﷺ."  

البيهقي:٢٧٢٦أَخْبَرَنَا أَبُو الْفَتْحِ مُحَمَّدُ بْنُ أَحْمَدَ بْنِ أَبِي الْفَوَارِسِ الْحَافِظُ بِبَغْدَادَ أنبأ أَبُو عَلِيِّ بْنُ الصَّوَّافِ ثنا أَبُو عَلِيٍّ بِشْرُ بْنُ مُوسَى ثنا أَبُو زَكَرِيَّا يَحْيَى بْنُ إِسْحَاقَ ثنا مَهْدِيُّ بْنُ مَيْمُونٍ عَنْ وَاصِلٍ الْأَحْدَبِ عَنْ أَبِي وَائِلٍ عَنْ حُذَيْفَةَ

أَنَّهُ مَرَّ عَلَى رَجُلٍ يُصَلِّي لَا يُتِمُّ رُكُوعًا وَلَا سُجُودًا فَقَالَ لَهُ مُذْ كَمْ تُصَلِّي هَذِهِ الصَّلَاةَ؟ فَقَالَ مُنْذُ أَرْبَعِينَ سَنَةً أَوْ قَالَ مُنْذُ كَذَا وَكَذَا قَالَ مَا صَلَّيْتَ لِلَّهِ صَلَاةً مُنْذُ كَذَا وَكَذَا قَالَ مَهْدِيٌّ وَأَحْسِبُهُ قَالَ لَهُ لَوْ مُتَّ لَمُتَّ عَلَى غَيْرِ سُنَّةِ مُحَمَّدٍ ﷺ  

رَوَاهُ الْبُخَارِيُّ فِي الصَّحِيحِ عَنِ الصَّلْتِ بْنِ مُحَمَّدٍ عَنْ مَهْدِيِّ بْنِ مَيْمُونٍ

See similar narrations below:

Collected by Aḥmad
ahmad:23360ʿAffān > Mahdī > Wāṣil al-Aḥdab > Abū Wāʾil > Ḥudhayfah

[Machine] He saw a man who did not complete the bowing or prostration, so when he finished his prayer, Hudhayfah called him and said to him, "How long have you been praying this prayer?" He replied, "I have been praying it for such and such time." Hudhayfah said to him, "You have not prayed, or you have not prayed a prayer for Allah, in the manner of the guided ones, and I believe that even if you die, you will die on a way other than the Sunnah of Muhammad ﷺ ."  

أحمد:٢٣٣٦٠حَدَّثَنَا عَفَّانُ حَدَّثَنَا مَهْدِيٌّ حَدَّثَنَا وَاصِلٌ الْأَحْدَبُ عَنْ أَبِي وَائِلٍ عَنْ حُذَيْفَةَ

أَنَّهُ رَأَى رَجُلًا لَا يُتِمُّ رُكُوعًا وَلَا سُجُودًا فَلَمَّا انْصَرَفَ مِنْ صَلَاتِهِ دَعَاهُ حُذَيْفَةُ فَقَالَ لَهُ مُنْذُ كَمْ صَلَّيْتَ هَذِهِ الصَّلَاةَ؟ قَالَ قَدْ صَلَّيْتُهَا مُنْذُ كَذَا وَكَذَا فَقَالَ حُذَيْفَةُ مَا صَلَّيْتَ أَوْ قَالَ مَا صَلَّيْتَ لِلَّهِ صَلَاةً شَكَّ مَهْدِيٌّ وَأَحْسِبُهُقَالَ وَلَوْ مُتَّ مُتَّ عَلَى غَيْرِ سُنَّةِ مُحَمَّدٍ ﷺ