ENOfficial
He reported God's messenger as saying, “If anyone recites Hā’ Mīm ad-Dukhān on a Thursday night his sins will be forgiven.” Tirmidhī transmitted it, saying that this is a gharīb da’īf tradition and that Hishām Abūl Miqdām its transmitter is declared to be weak.
Source: sunnah.com
Other translations
Arabic
وَعَنْ أَبِي هُرَيْرَةَ رَضِيَ اللَّهُ عَنْهُ قَالَ: قَالَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ: «مَنْ قَرَأَ (حم) الدُّخَانِ فِي لَيْلَةِ الْجُمْعَةِ غُفِرَ لَهُ» . رَوَاهُ التِّرْمِذِيُّ وَقَالَ: هَذَا حَدِيثٌ غَرِيبٌ وَهِشَام أَبُو الْمِقْدَام الرَّاوِي يضعف
sunnah.com