The Greek word that was translated “keep or Guard” here is “PHROUREO,” (froo·reh·o/) and it means “to be a watcher in advance, i.e. to mount guard as a sentinel (post spies at gates)” (Strong’s Concordance).
If we will condition ourselves to always walking in peace, God’s peace will protect us.
Anytime we begin to lose our peace, we should step back and identify the problem, see how what we are thinking on, and always remain in peace.
God’s peace acts as an umpire in our lives (Colossians 3:15).