فَهَلْ يَنْظُرُونَ إِلَّا السَّاعَةَ أَنْ تَأْتِيَهُمْ بَغْتَةً فَقَدْ جَاءَ أَشْرَاطُهَا فَأَنَّى لَهُمْ إِذَا جَاءَتْهُمْ ذِكْرَاهُمْ ﴿۱۸﴾ فَاعْلَمْ أَنَّهُ لَا إِلَهَ إِلَّا اللَّهُ وَاسْتَغْفِرْ لِذَنْبِكَ وَلِلْمُؤْمِنِينَ وَالْمُؤْمِنَاتِ وَاللَّهُ يَعْلَمُ مُتَقَلَّبَكُمْ وَمَثْوَاكُمْ ﴿۱۹﴾ وَيَقُولُ الَّذِينَ آمَنُوا لَوْلَا نُزِّلَتْ سُورَةٌ فَإِذَا أُنْزِلَتْ سُورَةٌ مُحْكَمَةٌ وَذُكِرَ فِيهَا الْقِتَالُ رَأَيْتَ الَّذِينَ فِي قُلُوبِهِمْ مَرَضٌ يَنْظُرُونَ إِلَيْكَ نَظَرَ الْمَغْشِيِّ عَلَيْهِ مِنَ الْمَوْتِ فَأَوْلَى لَهُمْ ﴿۲۰﴾

﴾18﴿ Fahal yanzuroona illas Saa'ata an ta'tiyahum baghtatan faqad jaaa'a ashraatuhaa; fa annaa lahum izaa jaaa'at hum zikraahum
﴾19﴿ Fa'lam annahoo laaa ilaaha illal laahu wastaghfir lizambika wa lilmu'mineena walmu'minaat; wallaahu ya'lamu mutaqallabakum wa maswaakum
﴾20﴿ Wa yaqoolul lazeena aamanoo law laa nuzzilat Sooratun fa izaaa unzilat Sooratum Muhkamatunw wa zukira feehal qitaalu ra aytal lazeena fee quloobihim maraduny yanzuroona ilaika nazaral maghshiyyi 'alaihi minal mawti fa'awlaa lahum

﴾18﴿ So these deniers wait for nothing except the Hour (of Judgment) to come upon them suddenly. But surely, its signs have already come. So how will their reminder benefit them when it (the Hour) has arrived
﴾19﴿ So know that there is no deity worthy of worship except Allah, and seek forgiveness for your sin and for the believing men and believing women. And Allah knows your movements and your place of rest
﴾20﴿ And those who claim to believe say, "Why has a surah not been sent down?" But when a decisive surah is revealed, and fighting is mentioned in it, you see those in whose hearts is a disease looking at you with the look of one overcome by the shadow of death. So woe to them

[18] This is an afterlife warning and mentions one state of the disbelievers—(بَغْتَةً): This refers to a moment whose exact time is unknown, so people are unprepared for it—it comes suddenly, even if its signs are known.
(فَقَدْ جَاءَ أَشْرَاطُهَا) – “Ashrāṭ” (signs) is originally used for marks left by wounds, and when healing begins, they are still visible. Here, it refers to the minor signs of the Hour, the first of which is the Prophethood of the Prophet (May Allah bless him and give him peace), as mentioned in the authentic hadith:
“I have been sent, and the Hour (is near), like these two”—referring to the closeness of his time and the Hour.
[19] This contains the declaration of Tawheed (Oneness of Allah), which is the objective of fighting (in the way of Allah). Its connection to the previous verse is that, after mentioning the nearness of the Hour, it now explains the way to be saved from the punishment of the Hour.
(فَاعْلَمْ) – The address is to the Prophet (May Allah bless him and give him peace), but the intent is his ummah, or it means remaining firm upon this knowledge.
The knowledge of this word (Lā ilāha illā Allāh) includes knowing its wording, its meaning, having belief in it, understanding its requirements, and acting upon it. This is evidence that the first obligation is the knowledge of Tawheed, and also that knowledge must come before speech and action.
(وَاسْتَغْفِرْ لِذَنْبِكَ) – Seeking forgiveness is both verbal and practical. It indicates that, along with knowledge, abundant istighfār (seeking forgiveness) is necessary.
(لِذَنْبِكَ) – The intended meaning of “sin” here is not actual sin, but rather the burden and grief upon the heart due to the shirk of the polytheists and the opposition of the disbelievers—meaning, say Astaghfirullāh to remove the heaviness from the heart. The evidence is in the hadith: “Indeed, there is a veil (or burden) cast over my heart, so I seek forgiveness from Allah seventy or a hundred times a day.”
Or, it may refer to occasionally leaving what is superior (al-afḍal), which is not sinful, but not suitable for those close to Allah. The third explanation, mentioned by Qurtubi, is: seek forgiveness to be saved from falling into sin.
(وَاللَّهُ يَعْلَمُ مُتَقَلَّبَكُمْ وَمَثْوَاكُمْ) – These two words include many meanings: (1) Your movements during the day and your places of rest at night. (2) Your deeds in this world and your final abode in the grave and the Hereafter. (3) Your traveling and settling in one place. Meaning: Allah the Exalted knows all your conditions.
[20] From this point—beginning from the second section to the end of the surah—there are warnings directed at the hypocrites, mentioning eighteen of their vices. There is also encouragement to fight (in verses 33 and 35), and encouragement to give in charity, along with a detachment from worldly life.
In verse (20), a warning is directed at the hypocrites by mentioning four of their conditions.
(الَّذِينَ آمَنُوا) – This is the statement of the sincere believers, who out of eagerness for jihad and longing to hear revelation, request its descent.
Or it refers to the hypocrites, who request the revelation of a surah in a hypocritical manner—similar to what is mentioned in Surah An-Nisā’ (4:77).