question #1 Sahih Muslim 144b, Book 1, Hadith 277 : What is the significance of retaining the sayings of the Prophet Muhammad (ﷺ) in one’s memory?

Verily yesterday when I was sitting with the Commander of the believers he asked his companions: When amongst you retains in his memory the utterance of the Messenger of Allah (ﷺ) with regard to the turmoil? -and he cited the hadith like the hadith narrated on the authority of Abu Khalid, but he did not mention the exposition of his words (Murbaddan) and (Mujakhiyyan).