Shared ground
These lines identify the letter’s main relationships from the start: Paul is the sender, the readers are a defined community, and the message begins with a blessing. Explicitly, Paul presents himself as “an apostle of Christ Jesus” and says this role is “through the will of God.” That frames his authority as received, not self-generated.
The recipients are described with two kinds of identity markers: where they are (“at Ephesus”) and who they belong to (“in Christ Jesus”). They are also called “saints” (people set apart as God’s people) and “faithful” (people characterized by loyalty or trust). The opening blessing asks for “grace” and “peace,” and it names their source as “God our Father and the Lord Jesus Christ,” keeping God and Jesus at the center.
Where interpretation differs (only where needed)
1) Whether “at Ephesus” was part of the original wording. Some argue the earliest form of the letter may have lacked a specific city name, making it more general-purpose; others argue “at Ephesus” was original and reflects a direct address to that city’s believers.
2) How “saints” and “faithful” relate. Some read the phrase as one group described in two ways (“the saints, namely the faithful”). Others think it may distinguish two overlapping descriptions (set-apart ones, and those showing ongoing loyalty), without implying two separate audiences.
3) What “in Christ Jesus” means. Everyone agrees it signals a defining connection to Jesus; the question is emphasis. Some stress union/participation (a new shared identity). Others stress allegiance (belonging to Jesus as Lord). The text itself is brief and does not spell out the mechanics.
Why the disagreement exists
The biggest uncertainty comes from how ancient copying sometimes handled place names in letter openings. The other differences come from how compact Greek phrases can be: a short line can be read as apposition (“that is”), as two descriptors side-by-side, or as a broader relational label. This greeting is more like a doorway than a full explanation, so later parts of the letter supply much of the detail.
What this passage clearly contributes
It establishes the letter’s claimed source and authority (“apostle… through the will of God”), the readers’ core identity (“saints… faithful… in Christ Jesus”), and the tone and content of the relationship: Paul’s words aim to convey God-given “grace” and “peace,” sourced from “God our Father and the Lord Jesus Christ.” It also previews the letter’s consistent God-and-Christ focus, which continues immediately in Ephesians 1:3.