Good morning! Paul writes to the Thessalonian church to do good to each other rather than repaying evil for evil. If this verse stands alone, we could determine what is “evil” and what is “good” by our own arbitrary standard.
This verse is found in the final portion of 1 Thessalonians, giving instructions and bestowing a benediction to that congregation. Among these instructions is found a fragment of a sentence which reads, “for this is the will of God in Christ Jesus for you” (1 Thess 5:18).
The Triune God (the Father, Son, and Holy Spirit) outlined his creative design for the world in the beginning. Anything outside of that is evil; anything that goes according to that is good–because He is good (see Luke 18:19).
In your walk with Christ, remember to love your neighbor as yourself. Make much of Jesus in your thinking, your speech, and your actions!