Passage
The Spirit quench not;
The Spirit quench not;
1 Thessalonians 5:17 continually pray ye;
1 Thessalonians 5:18 in every thing give thanks, for this <FI>is<Fi> the will of God in Christ Jesus in regard to you.
1 Thessalonians 5:19 The Spirit quench not;
1 Thessalonians 5:20 prophesyings despise not;
1 Thessalonians 5:21 all things prove; that which is good hold fast;
The verse centers on "Spirit" and "quench". It is saying that the verse draws attention to "Spirit" and "quench", so its meaning should be read from those terms before moving to application.
The nearby context moves from verse 18's "in every thing give thanks for this..." into verse 20's "prophesyings despise not...", so "Spirit" and "quench" 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 "Spirit" and "quench" with trust shaped by these words, not by a vague optimism outside the passage.