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.
bukhari:808al-Ṣalt b. Muḥammad > Mahdī > Wāṣil > Abū Wāʾil

Hudhaifa said, "I saw a person not performing his bowing and prostrations perfectly. When he completed the prayer, I told him that he had not prayed." I think that Hudhaifa added (i.e. said to the man), "Had you died, you would have died on a tradition other than that of the Prophet ﷺ Muhammad."  

البخاري:٨٠٨حَدَّثَنَا الصَّلْتُ بْنُ مُحَمَّدٍ قَالَ حَدَّثَنَا مَهْدِيٌّ عَنْ وَاصِلٍ عَنْ أَبِي وَائِلٍ

عَنْ حُذَيْفَةَ رَأَى رَجُلاً لاَ يُتِمُّ رُكُوعَهُ وَلاَ سُجُودَهُ فَلَمَّا قَضَى صَلاَتَهُ قَالَ لَهُ حُذَيْفَةُ مَا صَلَّيْتَ قَالَ وَأَحْسِبُهُ قَالَ وَلَوْ مُتَّ مُتَّ عَلَى غَيْرِ سُنَّةِ مُحَمَّدٍ ﷺ  


See similar narrations below:

Collected by Bukhārī

Importance of perfecting rukūʿ (bowing) and sujūd (prostration)

bukhari:791Ḥafṣ b. ʿUmar > Shuʿbah > Sulaymān > Zayd b. Wahb

Ḥudhayfah saw a person who was not bowing and prostrating perfectly ˹in prayer˺. He said to him, "You have not prayed; and if you should die you would die on a fiṭrah (natural disposition) other than that of the fiṭrah of Muhammad ﷺ."  

البخاري:٧٩١حَدَّثَنَا حَفْصُ بْنُ عُمَرَ قَالَ حَدَّثَنَا شُعْبَةُ عَنْ سُلَيْمَانَ قَالَ سَمِعْتُ زَيْدَ بْنَ وَهْبٍ قَالَ

رَأَى حُذَيْفَةُ رَجُلاً لاَ يُتِمُّ الرُّكُوعَ وَالسُّجُودَ قَالَ: مَا صَلَّيْتَ؛ وَلَوْ مُتَّ، مُتَّ عَلَى غَيْرِ الْفِطْرَةِ الَّتِي فَطَرَ اللَّهُ مُحَمَّدًا ﷺ۔  

bukhari:389al-Ṣalt b. Muḥammad > Mahdī > Wāṣil > Abū Wāʾil

Were you to die you would die on a "Sunna" (legal way) other than that of Muhammad ﷺ."  

البخاري:٣٨٩أَخْبَرَنَا الصَّلْتُ بْنُ مُحَمَّدٍ أَخْبَرَنَا مَهْدِيٌّ عَنْ وَاصِلٍ عَنْ أَبِي وَائِلٍ

عَنْ حُذَيْفَةَ رَأَى رَجُلاً لاَ يُتِمُّ رُكُوعَهُ وَلاَ سُجُودَهُ فَلَمَّا قَضَى صَلاَتَهُ قَالَ لَهُ حُذَيْفَةُ مَا صَلَّيْتَ قَالَ وَأَحْسِبُهُ قَالَ لَوْ مُتَّ مُتَّ عَلَى غَيْرِ سُنَّةِ مُحَمَّدٍ ﷺ