Passage
For yourselves know perfectly that the day of the Lord so cometh as a thief in the night.
For yourselves know perfectly that the day of the Lord so cometh as a thief in the night.
1 Thessalonians 5:1 But of the times and the seasons, brethren, ye have no need that I write unto you.
1 Thessalonians 5:2 For yourselves know perfectly that the day of the Lord so cometh as a thief in the night.
1 Thessalonians 5:3 For when they shall say, Peace and safety; then sudden destruction cometh upon them, as travail upon a woman with child; and they shall not escape.
1 Thessalonians 5:4 But ye, brethren, are not in darkness, that that day should overtake you as a thief.
The verse centers on "yourselves", "perfectly", "lord", "cometh", "thief", and "night". It is saying that the verse draws attention to "yourselves" and "perfectly", so its meaning should be read from those terms before moving to application.
The nearby context moves from verse 1's "But of the times and the seasons..." into verse 3's "For when they shall say Peace and...", so "yourselves" and "perfectly" belong inside that flow. In 1 Thessalonians context, the local focus is Christ, faith, and discipleship.
A plain takeaway is to answer the verse's own emphasis on "yourselves" and "perfectly" with trust shaped by these words, not by a vague optimism outside the passage.