In Scripture, the heart refers to the control center of one’s life. It is the central point of our thoughts, desires, and actions. We must guard it with all diligence. Proverbs 4:23 says that the springs of life flow from our hearts. In the spiritual battle, our hearts must be protected with the breastplate of righteousness.
Finally, be strong in the Lord and in the strength of his might. Put on the whole armor of God, that you may be able to stand against the schemes of the devil…put on the breastplate of righteousness…
The believer has been made right with God. When we trust in Christ alone as the only way to have a relationship with God, we are declared “Not guilty” and are clothed in the righteousness of Christ (2 Corinthians 5:21). We call this justification (Romans 3:24; 4:5). After we are justified, we begin to grow in our Christian life. We call this sanctification. It’s the believer’s sanctification that Paul is referring to when he tells us to “put on the breastplate of righteousness.” It is the “sanctifying righteousness”  of Christ that should be practiced.
Sometimes, we want to make the spiritual battle very complex and mysterious. We want to discuss and debate the cosmic powers and spiritual forces. But here, the spiritual battle becomes very simple. The breastplate of righteousness that guards the believer’s heart is summed up in one word: obedience. As one writer says, we are to “strive to be like Christ and live according to his ways of righteousness.” 
Righteous living is doing what is right in God’s eyes. That means we must read his Word, his love letter to us, where we are taught, reproofed, corrected, and trained “in righteousness” (2 Timothy 3:16). Studying God’s Word allows us to be in the process of sanctification so we “may be complete, equipped for every good work” (2 Timothy 3:17).
Will we live according to all the instruction of God’s Word perfectly? No. So, putting on the breastplate of righteousness includes owning our sin, confessing our sin, and, by God’s strength, turning from our sin.
Do you strap on the breastplate of righteousness every day? Are you battle ready?
Thank you for making us righteous and helping us to grow in righteousness. Help us guard our hearts by being in your Word every day and obeying it wholeheartedly. Help us to live battle ready. In Jesus’ name. Amen.
 Kenneth S. Wuest, Wuest’s Word Studies from the Greek New Testament: For the English Reader, vol. 4 (Grand Rapids: Eerdmans, 1997), 143.
 Max Anders, Galatians-Colossians, vol. 8, Holman New Testament Commentary (Nashville, TN: Broadman & Holman Publishers, 1999), 191.