Paul, Silvanus, and Timothy, to the assembly of the Thessalonians in God the Father and the Lord Jesus Christ: Grace to you and peace from God our Father and the Lord Jesus Christ.
which is in God the Father and in the Lord Jesus Christ: Each congregation has a spiritual as well as a geographical address. The geographical address for this group is Thessalonica (see the Introduction). Its spiritual address is "in God the Father and in the Lord Jesus Christ." Commenting on this verse, Wuest says this church "is in the sphere of God, circumscribed by God, surrounded by Him" (Nuggets 15). The preposition in "is frequently used by Paul to express intimacy of union" (Hogg and Vine 21).