William Burkitt on 2 Thessalonians 2:5

Observe here, That the doctrine of the rise and ruin of Antichrist is necessary to be made known; for though these things were not to come to pass in their days, yet St. Paul taught them before when present, and now repeateth it again when absent, to fasten it upon their mind and memories; it is necessary to deliver this doctrine, both to warn the faithful against delusion, and to fortify the faithful against persecution, and to keep them patient under it; for when Antichrist is discovered, Christians under his tyranny submit to sufferings more cheerfully: suffering under Antichristian persecutors is martyrdom and suffering for Christ, as well as under pagan persecutors.