question #1 Sahih al-Bukhari 766, Book 10, Hadith 160 : What is the significance of following the actions of the Prophet in Islamic practice?

I offered the `Isha’ prayer behind Abu Huraira and he recited, “Idha s-samaa’u n-shaqqat” (84) and
prostrated. On my inquiring, he said, “I prostrated behind Abul-Qasim (the Prophet) (when he recited
that Sura) and I will go on doing it till I meet him.”