﴿ نَّحْنُ أَعْلَمُ بِمَا يَسْتَمِعُونَ بِهِۦٓ إِذْ يَسْتَمِعُونَ إِلَيْكَ وَإِذْ هُمْ نَجْوَىٰٓ إِذْ يَقُولُ ٱلظَّٰلِمُونَ إِن تَتَّبِعُونَ إِلَّا رَجُلًۭا مَّسْحُورًا ﴾

“We are fully aware of what they are listening for when they listen to thee: for when they are secluded among themselves, lo! these wrongdoers say [unto one another], "If you were to follow [Muhammad, you would follow] only a man bewitched!"”

We know best what they listen to the reason for which they listen to it in order to mock it when they listen to you to your recital and when they are in secret counsel holding secret talks among themselves in other words when they talk when idh substitutes for the preceding idh ‘when’ the evildoers say in their secret conversation ‘You are only following a man bewitched one duped his mind overcome’.