مَّآ أَصَابَكَ مِنْ حَسَنَةٍ فَمِنَ ٱللَّهِ ۖ وَمَآ أَصَابَكَ مِن سَيِّئَةٍ فَمِن نَّفْسِكَ ۚ وَأَرْسَلْنَٰكَ لِلنَّاسِ رَسُولًا ۚ وَكَفَىٰ بِٱللَّهِ شَهِيدًا

When the Quranic instructions pertaining to sacrifice were revealed, the opportunists found them to be disturbing to the pattern of their lives. They started pretentious talk to hide their own weakness. The debacle at Uhud, they said, was due to the poor strategy of the Prophet, and thus they tried to misguide people about his ability to lead. Whenever something favourable happened, they associated it with the grace of God, simply to exhibit their faith in Islam; but to escape from the practical demands of Islam, they tried to prove the Prophet wrong. It is possible for man to show faith in God and continue to follow the dictates of his desires; but once he accepts allegiance with the messenger of God, it becomes necessary to stand by the side of the dayee, which is indeed a most difficult proposition.

— Source: Tazkirul Quran (Maulana Wahiduddin Khan) via Quran.com (4:79)