It is possible that Paul’s specific reference to peace and mercy is specially significant. He could be connecting with the situation in the Galatian churches, praying for peace because of the disruption caused by the Judaizers, and praying for mercy because that is what is needed on the final day of judgment. 1 Alternatively, given Paul’s previous references to the new creation and the coming of the Spirit, he could be alluding to a promise taken from Isaiah 54:1–17. 2 Previously, he quoted from this chapter (Galatians 4:27) to affirm that believers in Christ belong to the Jerusalem above and are the fulfilment of the restoration that what was promised through Isaiah. In that same chapter (Isaiah 54:10), the prophet also makes it clear that the Lord’s mercy (Septuagint) and peace are for this people (the church of Jesus Christ). 3
16 And as for all who walk by this rule, peace and mercy be upon them, and upon the Israel of God.