Muslim relates—on the authority of Jabir (may Allah be pleased with him)—that the Messenger of Allah ﷺ said, “Whoever meets Allah without associating anything with Him will enter Paradise, and whoever meets Him while associating anything with Him will enter the Fire.” (1)

Jabir: He is Jabir ibn ʿAbd-Allah ibn ʿAmr ibn Ḥarām al-Ansari al-Sulami, a distinguished Companion and prolific narrator, the son of a Companion. He died in Medina sometime after 70 AH at the age of ninety-four.

“Meets Allah”: that is, whoever dies.
“Does not associate anything with Him”: he takes no partner alongside Allah in either divinity or lordship.
“Anything”: whether the association is slight or great.

Overall meaning of the hadith: The Messenger ﷺ informs us that anyone who dies upon pure monotheism is certain to enter Paradise. If such a person committed a major sin and died persisting in it, he is under Allah’s will: should Allah pardon him, he will enter Paradise first; otherwise, he will be punished in Hell, then removed from it and admitted to Paradise.

Whoever dies upon major shirk will never enter Paradise, will receive no mercy from Allah, and will abide in Hell forever. If his shirk was minor, he will still enter the Fire—provided his good deeds do not outweigh it—but he will not remain there eternally.

Relevance to the chapter: the hadith delivers a grave warning against shirk, which necessitates intense fear of falling into it.