Small children underestimate danger.  As do naïve adults.  The expression, "take care" is often an affectionate parting expression - knowing that problems may exist but not really expecting any to come too close. But in war time, when the hazards are all too obvious, "take care" can become a final farewell.  Although treacherous, the battlefield experience is not just about survival; it is primarily about winning the war, and then establishing the peace.  The same is true for the Christian.  We are up against the forces of Satan who operates by deceiving the world with his lies (John 8:44):  yet we are also involved in presenting gospel truth to the deceived and winning them for Christ.  It will be dangerous, and there will be casualties, but locking ourselves away in an exclusive fellowship (a sort of sanctified bunker) is not our Commander's purpose.

This instruction to 'be careful' begins Paul's summing-up of his teaching about how to live as a Christian in a spiritual war-zone.  The dangers he has referred to are not primarily direct demonic encounters (although Ephesians 4:27 is clear that the devil is looking to gain a foothold in Christian lives).  Danger lies in the darkness of a world without God and in the lies that seduce the believer into the shadows (1 John 4:1).  In the same way that enemy spies target people with secrets to hide, so the Evil One is on the lookout for Christians who like to partly live in the darkness.  In the previous verses, Paul warned his readers about sleep-walking into the enemy's trap (Ephesians 5:8-14).   

The Lord wants us to be wise and not naïvely trapped, but also to seize the opportunities for the Kingdom of God. Indeed, those who look keenly for an opening to declare the gospel and want to glorify the Lord, will find that they will be less easily drawn into the evil around them.  Those who desire to live for Jesus will find the opportunities to speak for Him.  In this spiritual warfare, we not only wear body armour for protection but use God's Word to cut through lies which bind our Christless friends to their past and keep them from being liberated by the Lord Jesus (Ephesians 6:13-17).

Our commission is clear - to live as the children and ambassadors of the king (2 Corinthians 5:20).  Therefore, we should not live with an agenda of seeking personal pleasure or self-promotion.  It should be no surprise that this commission is to be lived out in our waking hours, which are mostly in our work time!  In some organisations it is said that you need to 'tread carefully'.  These verses, in the Greek, start by saying, "Look carefully how you walk ...". Let us remember that God's interests are at stake as we do our work today: what we say should reflect the policy of heaven, and what we do should enact the love of God.  Anything less and it is His image that slips with our colleagues - as well as our own.