Narrated 'Abd Allah (b. Mas'ud):

The Messenger of Allah (ﷺ) as saying: He who has in his heart as much pride as much pride as grain of mustard-seed will not enter paradise. And he who has in his heart as much faith as grain of mustard-seed will not enter Hell. Abu Dawud said: Al-Qasmali has transmitted it from Al-A'mash in a similar way.

حَدَّثَنَا أَحْمَدُ بْنُ يُونُسَ، حَدَّثَنَا أَبُو بَكْرٍ، - يَعْنِي ابْنَ عَيَّاشٍ - عَنِ الأَعْمَشِ، عَنْ إِبْرَاهِيمَ، عَنْ عَلْقَمَةَ، عَنْ عَبْدِ اللَّهِ، قَالَ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم ‏

‏ لاَ يَدْخُلُ الْجَنَّةَ مَنْ كَانَ فِي قَلْبِهِ مِثْقَالُ حَبَّةٍ مِنْ خَرْدَلٍ مِنْ كِبْرٍ وَلاَ يَدْخُلُ النَّارَ مَنْ كَانَ فِي قَلْبِهِ مِثْقَالُ خَرْدَلَةٍ مِنْ إِيمَانٍ ‏

‏ ‏.‏ قَالَ أَبُو دَاوُدَ رَوَاهُ الْقَسْمَلِيُّ عَنِ الأَعْمَشِ مِثْلَهُ ‏.‏