The greeting Paul wrote in most of his epistles was a combination of the commonly used Greek (charis, grace) and the Jewish (shalom, peace) salutations. The former in the Christian context refers to God"s undeserved favor that is the portion of His children. Galatians opens, closes (cf. Galatians 6:18), and is full of grace ( Galatians 1:6; Galatians 1:15; Galatians 2:9; Galatians 2:21; Galatians 3:18; Galatians 5:4). The actual Greek word is chairein, which means, "rejoice," but this standard Greek greeting meant the equivalent of "hello."[source]
"When Paul prays for grace on his friends, it is as if he said, "May the beauty of the wonder of the undeserved love of God be on you, so that it will make your life lovely too."" [1][source]
The second word of greeting, peace, defines not just the absence of hostility but the totality of God"s blessings. This word had become a standard Jewish greeting. Believers enjoy peace with God and with other people because God has taken the initiative in extending His grace to us in Christ (cf. Numbers 6:24-26). Peace always follows grace in Paul"s salutations because that is their logical and temporal order. The three-fold title "Lord Jesus Christ" indicates His exalted rank, His saving significance, and His divine commission respectively. [2][source]
Jesus Christ gave Himself for our sins in two respects. He gave Himself all through His earthly ministry as the Suffering Servant of God (cf. Isaiah 53), and He gave Himself as the final sin offering on the cross. Both aspects of His self-sacrifice could be in view here. Paul probably wanted to emphasize the totality of Christ"s self-sacrifice. [source][source][source]
The purpose of the Lord"s self-sacrifice was that He might deliver us out of the control of this present evil age, the world system that dominates the inter-advent era. In contrast, the age to come (cf. Ephesians 1:21) is the era in which righteousness dwells when Jesus Christ and later God the Father will rule directly (i.e, the messianic kingdom and the new heavens and earth). [source][source][source]
We are in the world, but we are free to live apart from the evil that dominates it thanks to Christ"s work for us. Not only Song of Solomon , the Lord will remove us from it by death or translation. Again, both aspects of our deliverance were probably in Paul"s mind as he wrote these words. Christ"s death transferred the believer from Satan"s power to God"s power, from one sphere to the other (cf. Colossians 1:13). [source][source][source]
"In this one verse Paul has described several aspects of the redemption wrought by Christ: its cause ("for our sins," that Isaiah , because of them), its means (Christ "sacrificed himself"), its purpose and effect ("for our sins," that Isaiah , for their expiation; "to rescue us"), and its origin ("the will of our God and Father"). Thereby Paul has in fact touched on the chief argument of the letter, and succinctly announced in anticipatory fashion the main contents of its doctrinal section, inasmuch as the point of the controversy between Paul and His Galatian opponents lies precisely in the significance of Christ and his redemptive work and more specifically in the bearing of this work on the law." [3][source]
"Another feature of this salutation is the extended description of the writer.... It conveys at once the impression of authority, which underlies the subsequent argument throughout the epistle." [4][source]