question #2 Sahih Muslim 823a, Book 6, Hadith 342 : What is the significance of verifying the pronunciation of Quranic words in Islamic tradition?

I saw a man asking Aswad b. Yazid who taught the Qur’an in the mosque: How do you recite the verse (fahal min muddakir) whether (the word muddakir) Is with (d) or (dh)? He (Aswad) said: It was with (d). I heard Abdullah b. Mas’ud saying that he had heard the Messenger of Allah (ﷺ) reciting (muddakir) with (d).