Hebrew shalom
Of the six Hebrew words translated “peace” in the Old Testament, only two relate to our modern concept of peace. The other four have to do with “holding your peace” or keeping quiet. These Hebrew words are unrelated to shalom. The other word is shelem, which is always used in connection with a “peace offering.” In Hebrew, vowels did not exist. So, in the earliest Hebrew, shalom and shelem would be the same. As the language developed, accent marks (called vowel pointers) were added to words to indicate the vowels, so shalom and shelem became different, the latter always being used in connection with that special offering under the Law.
Shalom is used in 213 different verses in the Old Testament. Fifty or so of them refer to the absence of strife, such as peace as opposed to war (Ecclesiastes 3:8). In another 25 cases, shalom is used as a greeting or farewell (e.g., Judges 19:20, 1 Samuel 25:6). The context surrounding the other two-thirds imply a peace that is more than a lack of war, but rather a peace of mind.
Even in the instances when shalom imparts the idea of an absence of strife, more than a lack of war is understood (Numbers 6:24-26, 1 Kings 4:25,5:4; 1 Chronicles 22:9-10, Lamentations 3:7). Peace is a work of righteousness (Psalm 34:14, Isaiah 32:17). The Law is called the Covenant of Peace (Numbers 25:12, Psalm 85:8, Ezekiel 34:25, Isaiah 54:10, Malachi 2:5). Dying in peace is a blessing (Genesis 15:15). Peace was to characterize the Messiah (Isaiah 9:6).
Greek eirene
Five Greek words are translated “peace” in the New Testament, but only eirene pertains to our modern concept of peace. Again, all the others refer to “holding your peace.”
The Greek equivalent of shalom was also used as a salutation and a blessing (Mark 5:34, Luke 7:50). Jesus gave the greeting special significance for the disciples (Luke 10:5, Matthew 10:13). Paul used peace as a salutation at the beginning of every letter of his. James noted that the salutation can be empty (James 2:16).
Angels promised the peace of God in announcing the Messiah (Luke 2:14), although Jesus did not promise peace for all (Matthew 10:34), but for Christians (John 14:27, John 16:33, Ephesians 2:14, 6:15). The coming of the Messiah portends peace in heaven (Luke 19:38). The Father is called the God of peace (Hebrews 13:20). Melchizedek, a symbol of the Christ, is called the king of peace (Hebrews 7:2).
This eirene is also used to describe our relationship to God when we are forgiven (Romans 5:1, Colossians 1:20). But that peace is more than a release from judgment (Philippians 4:7). Making peace is an act of righteousness (Matthew 5:9, Hebrews 12:14).
Peace is the opposite of confusion (1 Corinthians 14:33) and the desired normal state. Zacharias, the father of John the Baptist, contrasts peace with darkness and the shadow of death (Luke 1:79). The mind set on the Spirit is life and peace (Romans 8:6).
Peace is a gift from God (Romans 15:13) and mysteriously guards our hearts (Philippians 4:7). Yet it is something we pursue (2 Timothy 2:22, 1 Peter 3:11, 2 Peter 3:14) and which must rule in our hearts (Colossians 3:15). It is the peace of being reconciled to God.
Finally, this peace extends to the relationship between Christians, overcoming discord caused by issues which might seem important at the time, but, by comparison to brotherly love, are not (Romans 14:17, 1 Corinthians 7:15, Ephesians 4:3, James 3:18).