What is the significance of the breastplate of righteousness?

from the old testament

• Isaiah 59 speaks of Israel’s failings that create a separation from Him (Isaiah 59:2–8), followed by a confession (Isaiah 59:9–15a). However, his point is that God saves (Isaiah 59:1) and speaks about a coming Redeemer (Isaiah 59:20). Describing Him, Isaiah said, “He put on righteousness like a breastplate” (Isaiah 59:17a). This is the background for Paul’s “breastplate of righteousness” in Ephesians.

from the new testament

• In Ephesians 6:10–20, Paul gives the illustration of armor, saying “Put on the whole armor of God, that you may be able to stand against the schemes of the devil” (Ephesians 6:11). The “armor” is spiritual because “we do not wrestle against flesh and blood, but against the rulers, against the authorities, against the cosmic powers over this present darkness, against the spiritual forces of evil in the heavenly places” (Ephesians 6:12).
• Therefore, each piece of the armor represents some part of the Christian walk and how one can be protected from Satan’s “arrows” (Ephesians 6:16).
• As stated in the Old Testament section, Paul was drawing from Isaiah 59. Ephesians 6:14 reads, “Stand therefore … having put on the breastplate of righteousness.” Part of standing against Satan is this breastplate.
• Some have argued that Paul simply means to remind the believer that the believer is counted righteous because of Jesus' work. They are certainly correct that one can only be a believer by having Jesus’ righteousness credited to them (e.g., Romans 4:5).
• However, in Isaiah 59:17, Paul referred to the Redeemer—who is Jesus—as one who also puts on righteousness. So, while Paul might also be including the idea of credited righteousness, his point seems to be more on believers behaving righteously. Indeed, earlier in Ephesians, he said: “put off your old self, which belongs to your former manner of life and is corrupt through deceitful desires, and to be renewed in the spirit of your minds, and to put on the new self, created after the likeness of God in true righteousness and holiness” (Ephesians 4:22–24). This putting off the old, sinful self and putting on the new, redeemed self in righteousness appears to be Paul’s meaning in the armor passage.
• The idea of believers striving to be righteous, not to save themselves but to obey Jesus, is a common theme in the New Testament. As but one example, Peter taught, “as he who called you is holy, you also be holy in all your conduct, since it is written, “You shall be holy, for I am holy '” (1 Peter 1:15–16). Believers are to be like God by striving to be righteous, as Jesus was.
• In Ephesians 6, Paul says that by being righteous, one is protected to stand against Satan’s pressure to be unrighteous.
• Note: In Greek, certain phrases can be understood in various ways, with context determining the intended meaning. In this case, given the Isaiah 59 background, “breastplate of righteousness” should be understood as “appositional.” Appositional refers to the second word or phrase explaining or being synonymous with the first. Thus, in this case, what Paul likely meant was “put on the breastplate, which is righteousness.” Thus, rather than thinking of it as “a righteous breastplate,” putting on the breastplate represents putting on righteousness.

implications for today

The Christian life is one of ongoing spiritual warfare, but it’s not the type of war that some imagine. It’s not believers attacking Satan or demons. Instead, it’s an awareness that we really do have an enemy prowling around (1 Peter 5:8), and that we protect ourselves by cultivating spiritual practices such as prayer and reading Scripture. As we do, we are putting “on the whole armor of God” (Ephesians 6:10) so that “you may be able to withstand in the evil day, … to stand firm” (Ephesians 6:13).

One piece of equipment is putting on righteousness. That refers to more than being saved—though that’s certainly a requirement! It’s about living a life consistent with our confession. Being a disciple should never be merely theoretical. When Jesus tells us to obey His commands (John 14:15), He describes active obedience as one of God’s means of making us like Jesus (2 Corinthians 3:18). As we become more like Him, we respond to situations as He would.

Practicing righteousness (cf. 1 John 3:7) is a lot like learning martial arts or refining skills at the gun range. We practice so that if a dangerous situation arises, our “muscle memory” carries us through. We’re not distracted by thinking about counter blocks or proper weapon handling—that’s all second nature. Likewise, as we live righteously, we’re building a kind of spiritual muscle memory. By putting on the breastplate of righteousness daily, we train ourselves to respond intuitively to situations, such as looking away from sinful temptations (Job 31:1) or defusing a situation by responding to hostility with kindness (Proverbs 15:1).

If you are a disciple of Jesus, obeying Him will protect you and will demonstrate the heart of a true disciple of Jesus!