وَإِذْ تَأَذَّنَ رَبُّكُمْ لَئِن شَكَرْتُمْ لَأَزِيدَنَّكُمْ ۖ وَلَئِن كَفَرْتُمْ إِنَّ عَذَابِى لَشَدِيدٌۭ
Wa iz ta azzana Rabbukum la'in shakartum la azeedannakum wa la'in kafartum inn'azaabee lashadeed
Saheeh International
And [remember] when your Lord proclaimed, 'If you are grateful, I will surely increase you [in favor]; but if you deny, indeed, My punishment is severe.' "