Tafsir of Al-Muddathir 74:47

Until the certainty came to us: meaning death and its precursors, as the majority of exegetes have maintained. Ibn Atiyyah said: "In my view, 'certainty' is the verification of what they used to deny, namely returning to Allah the Exalted and the Hereafter." The statement of the exegetes that it is "death" is questionable in my view, because death itself is a certainty to the disbeliever while he is still alive. Therefore, by "certainty," they could only have meant the thing they used to deny while they were alive in the world, which they then became certain of after death. This concludes his statement, and there is some consideration in it.

Furthermore, the apparent meaning is that the sum of what they mentioned is the cause for the entry of all of them into the Fire, so it does not harm that there are among the people of the Fire some upon whom feeding the needy was not obligatory, such as destitute disbelievers. In al-Kashshaf, it is suggested that the speech may imply that the entry of each of them into the Fire is due to the sum of the four (sins mentioned), and it is also possible that the entry of some of them is due to only one of them, such as it being merely for abandoning prayer or abandoning the feeding of the needy. Within this lies a trace of Mu'tazilite doctrine, which is the eternal abiding in the Fire of one who commits a major sin among the believers, such as one who abandons prayer. You know that the verse is regarding the disbelievers, not anyone else among them.