Do you really believe in the spiritual realm? Do you believe there is a battle raging for the souls of men? It is hard to imagine that this is true if we are living in relative comfort and ease. But no matter our earthly situation, we need to think and live like soldiers.
In Ephesians 6:10-20, Paul is likely getting to the main point he wanted to make all along to the Christians in Ephesus. He frames the Christian life in light of the cosmic spiritual battle that is always going on, but about which we are often ignorant. Here spiritual forces of good and evil are clear and present, and their presence requires a wartime mentality. This war necessitates four imperatives: 1) be strong; 2) put on the full armor of God, 3) stand firm, 4) pray at all times.
Jesus delivered the decisive blow in the battle against the powers of darkness on the cross, but the battle still continues, and it is a matter of life and death, with eternal consequences (Eph. 6:12). The source of our strength and confidence in this conflict is always found in Christ (Eph. 1:19-20). We fight fearlessly because God “has delivered us from the domain of darkness and transferred us to the kingdom of his beloved Son” (Col. 1:13). Because of this, we can obey the main command of this passage, which is to “Stand firm” (Eph. 6:13). The armor imagery is from the Prophet Isaiah, who describes God as a warrior dressed for battle and defending His people (Isa. 11:4-5). With God leading the way into the fray, and with us wearing the armor He provides, we cannot lose.
We need to be prepared for the conflict, armed with God’s Truth both proclaimed and lived out (Eph. 6:14). Our lives should be marked by the righteousness that is ours in Christ, and with faith in what God provides. This enables us to resist the schemes of the Devil that would otherwise take us down. Ungodly behavior, doubt, and despair from within, and persecution and false teaching from the outside are deadly enemies, but they cannot stand against us when God is fighting for us. The salvation provided to us now and always in and through Christ, and Word of God are powerful enough to protect us and enable us to go on the offensive as well (v.17). Then we too can pray for boldness to be faithful ambassadors, even if we are in chains like the Apostle Paul.