Az-Zukhruf • BN-TAFSEER-IBN-E-KASEER
﴿ وَإِذَا بُشِّرَ أَحَدُهُم بِمَا ضَرَبَ لِلرَّحْمَٰنِ مَثَلًۭا ظَلَّ وَجْهُهُۥ مُسْوَدًّۭا وَهُوَ كَظِيمٌ ﴾
“For [thus it is:] if any of them is given the glad tiding of [the birth of] what he so readily attributes to the Most Gracious, his face darkens, and he is filled with suppressed anger:”
Please check ayah 43:20 for complete tafsir.