Surah An-Nisa 4:156

وَبِكُفْرِهِمْ وَقَوْلِهِمْ عَلَىٰ مَرْيَمَ بُهْتَـٰنًا عَظِيمًا

And [We cursed them] for their disbelief and their saying against Mary a great slander

Translation: Saheeh International

Tafsir

And for their disbelief a second time in Jesus the bā’ of bi-kufrihim ‘for their disbelief’ is repeated in order to separate it ‘their disbelief’ in Jesus from what is supplemented to it ‘their utterance against Mary’ and their uttering against Mary a tremendous calumny when they accused her of fornication.

Excerpt from Tafsir al-Jalalayn, commentary on 4:156, via Quran.com. The reader has the full commentary and 9 more tafsirs.