question #1 Sahih Muslim 193d, Book 1, Hadith 384 : What is the significance of professing ‘There is no god but Allah’ in relation to salvation from the Fire?

Verily the Apostle (ﷺ) said: He who professed: There is no god but Allah, would be brought out of the Fire even though he has in his heart virtue equal to the weight of a barley grain. Then he who professed: There is no god but Allah, would come out of the Fire, even though he has in his heart virtue equal to the weight of a wheat grain. He would then bring out from the Fire he who professed: There is no god but Allah, even though he has in his heart virtue equal to the weight of an atom. Ibn Minhal has made an addition (of these words) in his narration: Yazid said: I met Shu’ba and narrated to him this hadith. Shu’ba said: Qatada transmitted to us this hadith from Anas b. Malik who heard it from the Messenger of Allah (ﷺ) with this alteration that he substituted the word Zurra (grain) in place of Zarra (atom). Yazid said: Abu Bistam has made a change in it.