Some say 1 Thessalonians 5:5-10 says that one is to not “sleep”, but be sober and keep armor on in order to attain final salvation. Others say it means that we are children of the light so we are to put on this armor since we are going up. Which one is correct?
Your second statement is the more correct one. Paul was saying that unbelievers will be taken by surprise as the end times judgments approach but believers should not be surprised. Therefore when we see that the time is coming, we should be awake and alert as if we’re expecting it. The armor Paul mentioned represents faith, love, and hope. This is to guard our hearts (breastplate) and minds (helmet) against becoming complacent or discouraged. We can do this because we know that God did not appoint us to suffer wrath, but to receive the salvation that has been promised to us (1 Thes. 5:9), which includes being rescued (delivered) from the wrath to come (1 Thes. 1:10).