Following the Messenger is Better for the Believers

Allah said,

كَمَآ أَخْرَجَكَ رَبُّكَ

Then, the same event has been alluded to in the second verse (6): يُجَادِلُونَكَ فِي الْحَقِّ بَعْدَ مَا تَبَيَّنَ كَأَنَّمَا يُسَاقُونَ إِلَى الْمَوْتِ وَهُمْ يَنظُرُ‌ونَ (they were disputing with you about the truth after it became clear, as if they were being driven to a death being seen by them).

Though the noble Companions had not disobeyed any command given to them - in fact, what they had done was a certain expression of their weakness and lack of courage as part of their response when consulted. But, even such expression of personal opinion coming from the Companions of the Messengers of Allah when juxtaposed with the high station they were blessed with was unwelcome in the sight of Allah Ta` ala. Therefore, it was set forth in words which spell out displeasure.