(Fuswilath) 41 : 27
فَلَنُذِيقَنَّ الَّذِينَ كَفَرُوا عَذَابًا شَدِيدًا وَلَنَجْزِيَنَّهُمْ أَسْوَأَ الَّذِي كَانُوا يَعْمَلُونَ
Then We will make to taste those who disbelieved with the severe punishment, and We will reward them with the worst of what they had been doing.
The Best deed is to learn, teach, and propagate Adhikr, which is the Balance and Trust to keep the universe in its equilibrium, whereas the evil deed is to hide Adhikr and obstruct its propagation. See explanation 9: 67-68; 25: 33-34; 33: 72-73.