Huzaifa bin Yaman reported,

Hudhayfah saw a man who did not complete his bowing or prostration properly. When the man finished his prayer, Hudhayfah called him over and asked him, "How long have you been praying like this?"The man replied, "I have been praying this way for such and such a time."Hudhayfah said, "You have not prayed," or he said, "You have not prayed any prayer for Allah." Mahdi was uncertain, but he thought Hudhayfah added, "And if you were to die, you would die upon other than the way of Muhammad ﷺ."

Ahmad 23360

Sahih

حدثنا عفان حدثنا مهدي حدثنا واصل الأحدب عن أبي وائل

عن حذيفة

أنه رأى رجلا لا يتم ركوعا ولا سجودا فلما انصرف من صلاته دعاه حذيفة فقال له منذ كم صليت هذه الصلاة قال قد صليتها منذ كذا وكذا فقال حذيفة ما صليت أو قال ما صليت لله صلاة شك مهدي وأحسبه قال ولو مت مت على غير سنة محمد ﷺ

أحمد 23360صحيح
Contents
Reference
Commentary
Ayat
Collection
Musnad Ahmad
Book
Huzaifa bin Yaman
Numbering
Darussalam 23360
Ahmad 23360