2 Thessalonians 1:9-10
"These shall be punished with everlasting destruction from the presence of the Lord and from the glory of His power, when He shall come on that Day to be glorified in His saints and to be admired in all those who believe, because our testimony among you was believed."
Who will be punished? Those who know not God nor obey the Gospel of our Lord Jesus Christ (v.8). When will they be punished? On the DAY of His return with His mighty angels (v.7). Why? Because God is a righteous judge who will recompense with tribulation on those who trouble His children (v.6).
The Truth
"It is a fearful thing to fall into the hands of a living God." (Hebrews 10:31)