It has reached me that when Allah the Mighty and Majestic blesses a people and gives them some good He asks them to be grateful. If they are grateful, He is All-Able to give them more. But if they are ungrateful, He is all-able to turn His blessings into a punishment.
 

Al-Hasan Al-Basri – Allah have mercy on him [Al-Bayhaqi, Shu’ab Al-Iman article 4536]