1 Thessalonians 5:18 says to do what in every circumstance, for this is God's will for you?

Answer: Give thanks

"Give thanks in every circumstance, for this is God's will for you in Christ Jesus." (1 Thess 4:3 also calls sanctification God's will.)

“Give thanks in every circumstance, for this is God’s will for you in Christ Jesus.”— 1 Thessalonians 5:18 (BSB)