His saying: "The Reckoning for mankind has approached" means that it is near.
Yahya narrated from Khadash, from Abu Amir, from Abu Imran al-Jawni, who said: The Messenger of Allah (ﷺ) said: "When I was sent, the bearer of the Trumpet was sent, and he moved it toward his mouth, put one foot forward and one foot back, waiting for when he will be commanded to blow; so beware of the blowing [of the Trumpet]."
"And they are in neglect," meaning: the polytheists regarding the Hereafter,
"turning away" from the Quran.
قَوْله: ﴿اقْترب للنَّاس حسابهم﴾ أَيْ: أَنَّ ذَلِكَ قَرِيبٌ.
يَحْيَى: عَنْ خَدَاشٍ، عَنْ أَبِي عَامِرٍ، عَنْ أَبِي عِمْرَانَ الْجَوْنِيِّ قَالَ: قَالَ رَسُولُ اللَّهِ ﷺ: " حِينَ بُعِثَ إِلَيَّ بُعِثَ إِلَى صَاحِبِ الصُّورِ فَأَهْوَى بِهِ إِلَى فِيهِ، وَقَدَّمَ رِجْلًا وَأَخَّرَ رِجْلًا، يَنْتَظِرُ مَتَى يُؤْمَرْ يَنْفُخْ؛ أَلَا فَاتَّقُوا النَّفْخَةَ ". ﴿وَهُمْ فِي غَفلَة﴾ يَعْنِي: الْمُشْرِكِينَ عَنِ الْآخِرَةِ ﴿مُعْرِضُونَ﴾ عَن الْقُرْآن