Rafay Yadain
There are some narrations in this regard but all are considered weak (daif): https://sunnah.com/tirmidhi:257 https://sunnah.com/nasai:1026 https://sunnah.com/abudawud:750 To understand the principle of rafay dain and more importantly, which acts and azkar of Salah are obligatory and which are not, please refer to the videos provided in the following thread: Discussion 37566