“Seeing it is a righteous thing with God to recompence tribulation to them that trouble you:”
1611 King James Version (KJV)
1:6 It is a righteous thing with God - (However men may judge) to transfer the pressure from you to them. And it is remarkable that about this time, at the passover, the Jews raising a tumult, a great number (some say thirty thousand) of them were slain. St. Paul seems to allude to this beginning of sorrows, #1Th 2:16|, which did not end but with their destruction.
2Th 1:6 Seeing [it is] a righteous thing with God. Your trials prove a coming judgment, because it is a righteous thing for God to punish those who trouble you. They must be requited for their wrongs.