Breastplate

Biblical Texts

In the New Korean Revised Version, the term hosimgyeong (breastplate) appears only in the New Testament.

• Ephesians 6:14: "having on the breastplate of righteousness." The phrase occurs in the passage where Paul lists, one by one, the pieces of "the whole armour of God" that Christians are to put on (Ephesians 6:10–18).
• 1 Thessalonians 5:8: "putting on the breastplate of faith and love; and for an helmet, the hope of salvation." It appears within an exhortation to stay alert and wait for the day of the Lord (1 Thessalonians 5:1–11).
• Revelation 9:9, 9:17: The locusts that appear at the fifth trumpet "had breastplates, as it were breastplates of iron," and the horsemen who appear at the sixth trumpet are described as "having breastplates of fire, and of jacinth, and brimstone."

Word and Background

The Greek word thōrax refers to armor that covers the torso, especially the chest. The Sino-Korean term hosimgyeong literally means "mirror that guards the chest (heart)." It originally referred to a round metal plate attached to the chest of East Asian armor, and Korean Bible translators borrowed the term. The thōrax of the first-century Mediterranean world, however, was not a single round plate; it was armor made of chain mail, scales, or metal plates joined together to cover much of the torso. The New Korean Standard Version renders the word with the more descriptive gasummagi ("chest guard").

The breastpiece worn by the high priest (rendered "breastplate" in the KJV) was not armor but part of the priestly vestments, and it is a different object from the breastplate discussed here.

Old Testament Background and New Testament Usage

Paul's expression is widely understood to draw on Isaiah 59:17, where God "put on righteousness as a breastplate, and an helmet of salvation upon his head." The Septuagint renders "breastplate" in this verse as thōrax, and a similar expression appears in the apocryphal Wisdom of Solomon. Notably, the armor that God wears in the Old Testament is worn by believers in the New Testament.

Interpretation and Issues

• The meaning of "righteousness": Interpreters differ over the meaning of "righteousness" in Ephesians 6:14. One view reads it as the righteousness Christ gives, that is, the righteousness of justification. Another reads it as the righteousness of upright living, that is, sanctification. Many interpreters in the Reformed tradition emphasize the former view, while the Wesleyan tradition tends to emphasize the aspect of holy living as well. Many commentators hold that the term carries both meanings.
• The flexibility of the metaphor: In 1 Thessalonians, the same breastplate stands for faith and love. For this reason, some hold that readers should grasp the meaning of the metaphor as a whole rather than assign a single fixed meaning to each piece of armor. The triad of faith, love, and hope in 1 Thessalonians 5:8 also connects with 1 Thessalonians 1:3.
• A popular embellishment: Sermons frequently include the saying, "The whole armor of God has nothing to cover the back, so do not retreat." The text, however, says nothing of the kind, and actual thōrakes often covered the back as well.
• The breastplates in Revelation: How the breastplates of the locusts and the horsemen are understood depends on one's approach to interpreting Revelation (Seven Seals, Trumpets, and Bowls). Some popular interpretations liken them to modern weapons, but scholars generally read them as symbols within a vision.

In the Korean Church

Because hosimgyeong is rarely used in modern Korean, preachers often explain its meaning in sermons. The whole armor of God in Ephesians 6 is a staple text for sermons on spiritual warfare. In Sunday schools and at retreats, teachers sometimes make drawings or props of the helmet, breastplate, shield, and other pieces to illustrate the passage.