Shared ground
These closing lines present God as the active giver of what the community needs after hard instruction: peace, presence, and grace. The wording is broad and repetitive (“all,” “at all times,” “in all ways”), keeping the focus on the whole church, not just the people Paul has just corrected. “Lord of peace” identifies the Lord as the source and giver of peace, not merely a topic of peace-talk. The final blessing (“grace … be with you all”) matches the earlier wish (“The Lord be with you all”), tying the community together under a shared gift.
Paul also emphasizes authenticity. He says this closing greeting is written “with my own hand” and that his handwriting functions as a recognizable sign “in every letter.” That implies the message carries authorized weight, and it also addresses a real-world problem: churches could receive messages that claimed to be from apostolic leaders.
Where interpretation differs (only where needed)
“Peace … in all ways” (v. 16): Some read this mainly as “in every circumstance” (peace no matter what happens). Others hear “in every way” as “in every kind or manner” (peace expressed through multiple forms—inner steadiness, restored relationships, communal harmony). Both readings keep the request wide rather than narrow.
“Sign in every letter” (v. 17): Some take this as a strict claim that Paul always added a handwritten line to authenticate each letter. Others understand it more generally: Paul’s handwriting style served as a known marker when he did write personally, without requiring that every letter had the same kind or amount of handwritten material.
Why the disagreement exists
The Greek wording behind “in all ways” can point either to different situations or different kinds/manners. And “in every letter” can be read as a consistent habit or as a general description of how his letters can be recognized, especially since letters in antiquity were often written through a scribe with only a short personal note added.
What this passage clearly contributes
Explicitly, the text presents the Lord as the giver of peace “at all times,” extends the blessing to “all” in the community, and closes by asking for the Lord’s grace to be “with you all.” It also explicitly ties Paul’s personal handwriting to the authenticity of his letters (“This is how I write”). Theologically (by inference), the passage shows that early churches treated apostolic communication as something that needed verification in a setting where confusion or false claims could circulate, and that peace and grace are framed as ongoing divine gifts, not merely the result of better community management.