27. By the letter and circumcision, etc. A construction (85) which means a literal circumcision. He does not mean that they violated the law, because they had the literal circumcision; but because they continued, though they had the outward rite, to neglect the spiritual worship of God, even piety, justice, judgment, and truth, which are the chief matters of the law. (86)
(85) Hypallage, substitution, a figure of speech, by which a noun or an adjective is put in a form different from its obvious import. — Ed
(86) The rendering of this clause is rather obscure, “who by the letter and circumcision dost transgress the law.” The preposition, διὰ, has no doubt the meaning of ἐν or σύν, as in some other passages, as in Romans 4:11, δἰ ἀκροβυστίας — in uncircumcision, and in Romans 8:25, δἰ ῦπομονὢς — in or with patience. Then the version should be, “who, being with, or having, the letter and circumcision, dost transgress the law.” The “letter” means the written law. That this is the meaning is evident from the context. Both [ Grotius ] and [ Macknight ] give the same construction. It is better to take “letter,” i.e. , the law, and “circumcision” separate, than to amalgamate them by a rhetorical figure, as is done by [ Calvin ] and others. [ Hodge ] justly says, that this is “more suited to the context, as nothing is said here of spiritual circumcision.”
The word γράμμα, letter, has various meanings — 1. What is commonly called letter, the character, Luke 23:38, — 2. What is written, a bond or contract, Luke 16:6; — 3. In the plural, letters, epistles, Acts 28:21; — 4. The written law, as here, and in the plural, the Old Testament Scriptures, 2 Timothy 3:15; — 5. What is conveyed by writing, learning, John 7:15; Acts 26:24; — and, 6. The outward performance of the law, it being written, as opposed to what is spiritual or inward, as in the last verse of this chapter, and in 2 Corinthians 3:6. — Ed