Paul speaks of knowing the truth about God as belonging to the day. AT: "we know the truth" or "we have received the light of truth" (See: [[rc://en/ta/man/translate/figs-metaphor]])
As a soldier would put on a breastplate to protect his body, a believer who lives by faith and love will find protection. AT: "protect ourselves with faith and love" or "protect ourselves by trusting Christ and loving him" (See: [[rc://en/ta/man/translate/figs-metaphor]])
As a helmet protects a soldier's head, assurance of salvation protects the believer. AT: "protect ourselves by being certain that Christ will save us" (See: [[rc://en/ta/man/translate/figs-metaphor]])