The disciples too were affected by prejudice. To be united, they would have to change their mind - set.
وَهٰذَا لِأَنَّ ٱلنَّاسَ كَانُوا مُتَكَبِّرِينَ بِسَبَبِ دِينِهِمْ ،‏ عِرْقِهِمْ ،‏ وَمَرْكَزِهِمِ ٱلِٱجْتِمَاعِيِّ .‏