حَدَّثَنَا حَفْصُ بْنُ عُمَرَ، حَدَّثَنَا شُعْبَةُ، عَنْ أَبِي إِسْحَاقَ، عَنِ الأَسْوَدِ، عَنْ عَبْدِ اللَّهِ، أَنَّ النَّبِيَّ صلى الله عليه وسلم كَانَ يَقْرَؤُهَا ‏{‏ فَهَلْ مِنْ مُدَّكِرٍ ‏}‏ يَعْنِي مُثَقَّلاً ‏.‏ قَالَ أَبُو دَاوُدَ مَضْمُومَةَ الْمِيمِ مَفْتُوحَةَ الدَّالِ مَكْسُورَةَ الْكَافِ ‏.‏

Narrated Abdullah ibn Mas'ud: The Prophet (PBUH) used to read the verse "Is there any that will receive admonition (muddakir)? " that is with doubling of consonant [(dal)(d)]. Abu Dawud said: The word muddakir may be pronounced as mim (m) with a short vowel u. (dal)(d) with a short vowel and kaf (k) with a short vowel i. Translation Not Available

Book Ref: Sunan Abi Dawud Book 32 Hadith 3994
Web Ref:  Sunan Abi Dawud Book 31 Hadith 3983