﴿ قَدْ نَعْلَمُ إِنَّهُۥ لَيَحْزُنُكَ ٱلَّذِى يَقُولُونَ ۖ فَإِنَّهُمْ لَا يُكَذِّبُونَكَ وَلَٰكِنَّ ٱلظَّٰلِمِينَ بِـَٔايَٰتِ ٱللَّهِ يَجْحَدُونَ ﴾

“Well do We know that what such people say grieves thee indeed: yet, behold, it is not thee to whom they give the lie, but God's messages do these evildoers deny.”

We know indeed qad is a confirmative particle that it grieves you that matter which they say to you in denial; yet it is not that they deny you in secret for they know that you are truthful a variant reading for lā yukadhdhibūnaka ‘not that they deny you’ has lā yukdhibūnak that is to say ‘they do not associate you with mendacity’ but evildoers al-zālimīn replaces the previous pronominalisation ‘they’ knowingly reject deny the signs of God the Qur’ān.