2 Thessalonians 3:17,18

Conclusion. Paul now takes the pen from his amanuensis, to add the salutation in his own handwriting for the purpose of authenticating the epistle (otherwise in 1 Corinthians 16:21). This, he observes, is the sign-manual of his letters (cf. 2 Thessalonians 2:2), i.e., the fact of a personal written greeting at the close, not any form of words (like 2 Thessalonians 3:18), or the use of the word “grace,” or “certum quendam nexum literarium” (Grotius). The precaution is natural, in view of his suspicion about unauthorised communications. Compare “the σεσημείωμαι (generally contracted into σεση) with which so many of the Egyptian papyrus-letters and ostraca close” (Milligan, p. 130), or the postscript in one's own handwriting (ξύμβολον) which guaranteed an ancient letter (Deissmann: Licht vom Osten, 105). μετά (cf. 2 Thessalonians 3:16), the divine presence is realised through the experience of Christ's grace.