divine knowledge (ilm Allah)

ذَٰلِكَ بِأَنَّهُمْ قَالُوا۟ لِلَّذِينَ كَرِهُوا۟ مَا نَزَّلَ ٱللَّهُ سَنُطِيعُكُمْ فِى بَعْضِ ٱلْأَمْرِ ۖ وَٱللَّهُ يَعْلَمُ إِسْرَارَهُمْ

That is because they said to those who disliked what Allāh sent down, "We will obey you in part of the matter." And Allāh knows what they conceal.