Masruq (may Allah have mercy on him) says that once a man came to Sayyiduna Ibn Mas’ud (may Allah be pleased with him) and said,“I am coming from the mosque where I left a man who is explaining the Qur’an according to his own opinion. He is saying in the explanation of this verse: «﴿يَوْمَ تَأْتِي السَّمَاءُ بِدُخَانٍ مُبِينٍ﴾ [الدخان: 10] » ‘The Day when a clear smoke will appear in the sky,’ that this smoke will envelop them on the Day of Resurrection and will enter their breaths, causing a state like catarrh.”Upon hearing this, Sayyiduna Ibn Mas’ud (may Allah be pleased with him) said,“Whoever knows something well may explain it, and whoever does not know something well should say, ‘Allah knows best,’ for it is also a sign of a person’s wisdom that he says, regarding what he does not know, ‘Allah knows best.’ This verse was revealed in the context that when the Quraysh exceeded all limits in disobeying the Prophet (peace and blessings be upon him), the Prophet (peace and blessings be upon him) supplicated for a famine upon them like that in the time of Yusuf (peace be upon him). Thus, the Quraysh were surrounded by famine and hardship, to the extent that they were forced to eat bones, and the situation became such that when a person looked towards the sky, due to hunger, he would see smoke between himself and the sky. At this, Allah the Exalted revealed this verse: «﴿فَارْتَقِبْ يَوْمَ تَأْتِي السَّمَاءُ بِدُخَانٍ مُبِينٍ o يَغْشَى النَّاسَ هَذَا عَذَابٌ أَلِيمٌ﴾ [الدخان: 10-11] » ‘So wait for the Day when the sky will bring a clear smoke, enveloping the people; this will be a painful punishment.’ After this, some people came to the Prophet (peace and blessings be upon him) and said, ‘O Messenger of Allah (peace and blessings be upon him)! Pray for rain for the Banu Mudar, for they are perishing.’ So the Prophet (peace and blessings be upon him) prayed for them, and this verse was revealed: «﴿إِنَّا كَاشِفُو الْعَذَابِ﴾ [الدخان: 15] » ‘We will remove the punishment from them.’ But when they returned to their former ways after prosperity returned, this verse was revealed: «﴿يَوْمَ نَبْطِشُ الْبَطْشَةَ الْكُبْرَى إِنَّا مُنْتَقِمُونَ﴾ [الدخان: 16] » ‘The Day We will seize them with the greatest seizure, We will indeed take retribution,’ and this refers to the Battle of Badr.”