Severe
Those who stray will face severe punishment for neglecting the Day of Reckoning.
38:26(And it was said unto him): O David! Lo! We have set thee as a viceroy in the earth; therefor judge aright between mankind, and follow not desire that it beguile thee from the way of Allah. Lo! those who wander from the way of Allah have an awful doom, forasmuch as they forgot the Day of Reckoning.
65:8And how many a community revolted against the ordinance of its Lord and His messengers, and We called it to a stern account and punished it with dire punishment,