And [We cursed them]1 for their breaking of the covenant and their disbelief in the signs of Allāh and their killing of the prophets without right and their saying, "Our hearts are wrapped" [i.e., sealed against reception]. Rather, Allāh has sealed them because of their disbelief, so they believe not, except for a few.2
Translation: Saheeh International (English)
1 Another interpretation is "And [We made certain good foods unlawful to them]," based upon verse 160.
I distanced them from My mercy because they broke the promise that was taken from them, disbelieved in Allah’s words, boldly killed the prophets and said to Muhammad (peace be upon him), 'Our hearts are covered, so we cannot understand what you say’ That is not the case. Instead, Allah has sealed their hearts so no good reaches them. They only have a little faith, which will not be of any use to them.