# we belong to the day

Paul speaks of knowing the truth about God as belonging to the day. Alternate translation: "we know the truth" or "we have received the light of truth” 

# we must stay sober

Paul compares being sober to exercising self-control. Alternate translation: “let us exercise self-control” 

# put on faith and love as a breastplate

As a soldier would put on a breastplate to protect his body, a believer who lives by faith and love will find protection. Alternate translation: "protect ourselves with faith and love" or "protect ourselves by trusting Christ and loving him” 

# the hope of salvation for our helmet

Here "hope of salvation" means a certainty that Jesus will save his people. As a helmet protects a soldier's head, assurance of salvation protects the believer. Alternate translation: "protect ourselves by being certain that Christ will save us”