ISB ~ 2 Thessalonians 2 v2

shaken … or excited:False prophets are unsettling Paul’s readers, whose suffering and affliction seem to reinforce allegations that the tribulation of the last days is under way and is about to give way to the Second Coming (1:6; 1 Thess 2:14).

by spirit or by word:i.e., by charismatic revelations. These need to be measured against apostolic teaching in order to test their authenticity (1 Cor 14:29; 1 Thess 5:20-21).

by letter:i.e., by a forged document claiming to come from Paul, Silvanus, and Timothy (1:1). Paul considers this a form of deception (2:3).

the day of the Lord:The Day of Judgment. See note on 1 Thess 5:2.