[Is there in their hearts a disease?] which is shirk (polytheism). [Or have they doubted?] meaning they doubted Allah and His Messenger. He said this in the form of an inquiry, meaning: they have indeed done that. [Or do they fear that Allah will be unjust] meaning: that Allah will oppress [to them, or His Messenger?] meaning: they have indeed feared that.
﴿أَفِي قُلُوبهم مرض﴾ وَهُوَ الشّرك ﴿أم ارْتَابُوا﴾ شَكُّوا فِي اللَّهِ وَفِي رَسُولِهِ؛ قَالَهُ عَلَى الِاسْتِفْهَامِ؛ أَيْ: قَدْ فَعَلُوا ذَلِكَ ﴿أَمْ يَخَافُونَ أَنْ يَحِيف الله﴾ أَي: يجوز الله ﴿عَلَيْهِم وَرَسُوله﴾ أَي: قد خَافُوا ذَلِك
