Wa-ith taaththana rabbukumla-in shakartum laazeedannakum wala-in kafartum inna AAathabeelashadeed
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.'"
If you are grateful, I will surely increase you. Gratitude is compound interest on blessings.