for that day
The order of events is:
(1) The working of the mystery of lawlessness under divine restraint which had already begun in the apostle's time (2 Thessalonians 2:7).
(2) the apostasy of the professing church (2 Thessalonians 1:3); (Luke 18:8); (2 Timothy 3:1-8).
(3) the removal of that which restrains the mystery of lawlessness (2 Thessalonians 2:6); (2 Thessalonians 2:7). The restrainer is a person -- "he," and since a "mystery" always implies a supernatural element,
( See Scofield) - (Matthew 13:11),
this Person can be none other than the Holy Spirit in the church, to be "taken out of the way"; (2 Thessalonians 2:7); (1 Thessalonians 4:14-17).
(4) the manifestation of the lawless one (2 Thessalonians 2:8-10); (Daniel 7:8); (Daniel 9:27); (Matthew 24:15); (Revelation 13:2-10).
(5) the coming of Christ in glory and the destruction of the lawless one (2 Thessalonians 2:8); (Revelation 19:11-21).
(6) the day of Jehovah (2 Thessalonians 2:9-12); (Isaiah 2:12).