The greeting of Paul in my own hand, which is the mark in every letter, so I write 18 The grace of our lord Jesus Christ be with all of you. If longer reading was original , and no reason why it would have been deleted. Rather evenly balanced external attestation with and without. Arose through conformation to prev. Doesn't make too much sense.
External evidence is ambiguous, though.
It is absent from good representatives of both the Alexandrian and the Western text-types. Or could have been dropped, by homoeotelenton. Evidence for r. 1, through possibly an assimilation to GR Is. Its dialectic termination was corrected very frequent in the GR acc. Since the GR is surprising in the context which involves such frequent reference 2 ppl, the introduction of the predominantly Western reading GR is perhaps to be expected.