COMMENTARY on 4:156
Mustafa Khattab:

Translation:
and for their denial and outrageous accusation against Mary,45
Commentary:
45   i.e., they slandered Mary by claiming that she conceived Jesus through an illegal relationship.

 

A. Yusuf Ali:

Translation:
That they rejected Faith; that they uttered against Mary a grave false charge; 662
Commentary:

662  The false charge against Mar)' was that she was unchaste, Cf. 19:27 -28. Such a charge is bad enough to make against any woman, but to make it against Mary, the mother of Jesus, was to bring into ridicule Allah's power itself. Islam is specially strong in guarding the reputation of women. Slanderers of women are bound to bring four witnesses in support of their accusations, and if they fail to produce four witnesses, they are to be flogged with eighty stripes and debarred forever from being competent witness: 24:4.

 

Muhammad Asad:

Translation:
and for their refusal to acknowledge the truth, and the awesome calumny which they utter against Mary, 170
Commentary:
170  The calumny referred to is the popular Jewish assertion that Jesus was an illegitimate child.