question #3 Sahih al-Bukhari 790, Book 10, Hadith 185 : How did the companions of the Prophet ensure they were following the correct practices in prayer?

I offered prayer beside my father and approximated both my hands and placed them in between the
knees. My father told me not to do so and said, “We used to do the same but we were forbidden (by
the Prophet) to do it and were ordered to place the hands on the knees.”