Abdullah Ibn-e-Umar (rta) Strict Adherence To Rafa Ya Dain Making It Obligatory
Emphasis on Rafa Yadayn suggests that it was not an obligatory part, or a frequent practice, and people used to say prayer without it. The cited tradition itself confirms it. Saying prayer without Rafa Yadain was a normal practice, therefore Rafa Yadain which was not so common, was emphasized by some. Please refer to the following video: https://www.youtube.com/watch?v=LYL5fuqOdxg