2 Thessalonians 1:7-10 is discussing unbelievers who reject God, and reject the Lord Jesus Christ as their savior, people who will be dead in their sins as a result.
But your post was countering the statement that "Sin is anything that seperates you from God" which was in response to "What is "Sin"?, and you make no distinction btwn believers and the lost,
Believers because they believe are in Christ, and thus follow Him and repent when convicted that they did not in some way. God also exhorts to continue in the confidence, and warns against departing from the faith, (Heb. 3:6,12,14; 10:26,38; Gal. 5:1-4) by which faith ye are saved, and works to bring them to repentance if need be, lest they be condemned with the world.(1Cor. 11:32)
Thanks be to God.