We have now to inquire why in some of Paul's epistles the salutation is only in his name; some have merely, “Grace be with you,” and others a fuller form.
1 Timothy alone is individual, σοῦ. In Titus it is, “be with you all.” The general fact stands thus: “The grace of the Lord Jesus Christ,” or our Lord Jesus Christ, which last is more general (2 Corinthians adding, love of God and fellowship of the Holy Ghost), found in Rom. 1 and 2 Corinthians, Galatians, Phil. 1 and 2 Thessalonians, and Philemon; “Grace be with you,” or with you all, in Ephesians, Col. 1 and 2 Timothy, Titus, and Hebrews, The former seems more elaborate and formal from one sitting down to address them as an apostle commissioned so to teach them from Christ, and speaking from Him in a didactic way; the latter, the personal expression of his own feeling, the wish of his heart. He had finished what he had to say, and then closes by wishing them grace, a natural feeling. The former was a formal part of the epistle, and which he added formally. In the latter he had finished what he had to say, and wishes them grace. In 1 and 2 Timothy this is natural, and in Titus.
There remain only Ephesians, Colossians, and Hebrews. In Eph. 6:24 it is clearly a distinct and personal wish of his heart, as is manifest from what precedes, and it closes according to the former character, and the objects which follow. So in Colossians it is expressly his personal salutation, written with his own hand. The same character is in Hebrews, which is in fact a treatise, not an epistle. What is epistolary, the last verses, is finished. Ephesians and Colossians are pretty much treatises too, but addressed formally to certain saints. Romans is in a great measure a treatise, but in an epistolary form, the last part fully so, and the salutation forms part of it.