The grace of our Lord Jesus Christ be with you all; - See the notes, Romans 16:20.
From the subscription to this Epistle, it purports to have been "written from Athens." This is probably incorrect, as there is reason to think that it was written from Corinth. See the introduction. At all events, this subscription is of no authority. See the notes at the end of the Epistles to the Romans and 1-Corinthians.

The grace - The favor, blessing, and influence of our Lord Jesus Christ, be with you all - be your constant companion. May you ever feel his presence, and enjoy his benediction!
Amen - So let be! God grant it! This word in this place, has more evidence in favor of its genuineness than it has in most other places; and was probably added here by the apostle himself, or by the Church of the Thessalonians.
The subscriptions to this epistle are various in the MSS. and Versions. The latter are as follows: -
The Second Epistle to the Thessalonians was written from Athens. - Common Greek text.
The Second Epistle to the Thessalonians, which was written at Laodicea in Pisidia, was sent by the hands of Tychicus. - Syriac.
The end of the Epistle; and it was written at Athens. - Arabic.
To the Thessalonians. - Aethiopic.
Written from Athens, and sent by Silvanus and Timotheus. - Coptic.
No subscription in the Vulgate.
Written at Corinth. - Author of the Synopsis.
- sent by Titus and Onesimus. - Latin Prologue.
The Second Epistle to the Thessalonians, written from Rome. - No. 71, a MS. of the Vatican library, written about the eleventh century.
The chief of the MSS. either have no subscription, or agree with some of the above versions.
That the epistle was neither written at Athens, Laodicea, nor Rome, has been sufficiently proved; and that it was written, as well as the first, at Corinth, is extremely probable. See the preface, and what has been said on the preceding epistle.
I have often had occasion to observe that the subscriptions at the end of the sacred books are not of Divine origin; they are generally false; and yet some have quoted them as making a part of the sacred test, and have adduced them in support of some favourite opinions.
Finished correcting this epistle for a new edition, the shortest day in 1831. - A. C.

The grace of our Lord Jesus Christ be with you all. Amen. This was the sign or token; See Gill on Romans 16:20 The subscription to this epistle is, "The Second Epistle to the Thessalonians was written from Athens"; though it seems rather to be written from Corinth. In the Syriac version it is said,
"the Second Epistle to the Thessalonians, which is written from Laodicea of Pisidia, and sent by the hands of Tychicus.''

He closes every Epistle by praying for GRACE to those whom he addresses.
Amen--omitted in the oldest manuscripts It was doubtless the response of the congregation after hearing the Epistle read publicly; hence it crept into copies.
The Subscription is spurious, as the Epistle was written not "from Athens," but from Corinth.