16 Now may the Lord of peace Himself give you peace always in every way. The Lord be with you all.
17 The salutation of Paul with my own hand, which is a sign in every epistle; so I write.
18 The grace of our Lord Jesus Christ be with you all. Amen.
Now (v.16) — Paul did his best to ease the Thessalonians’ fears and settle the unrest in the church caused by busybodies, so now he pointed them to the resource that could make it possible—the Lord. (See 1 Thessalonians 5:23.)
Himself (v.16) — giving emphasis to “the Lord of peace,” the only one who could offer real peace. It also conveys God’s personal concern for His own.
peace (v.16) — The prayer is not for the cessation of persecution, nor yet of the internal disorders from which they suffered, but for that calm of heart which comes of faith in God and is independent of circumstances. — Vine, page 136.
always (v.16) = through all, continually
The salutation of Paul with my own hand (v.17) — It’s likely that Paul dictated the letter to someone else who wrote the actual words, but Paul took the pen and signed his own name at the bottom.
sign (v.17) — Like a signature on a check, Paul’s signature on a letter proved its authenticity.
In every one of Paul’s epistles, except that to the Hebrews, he signs his name personally, always at the opening and thrice also at the close (1 Corinthians, Colossians, and 2 Thessalonians). He learned to do this early in his writing career, for it was at Thessalonica that someone had forged his name to a letter, or had in some way made it appear that he had written it. — Stam, page 144.