Brethren, I speak after the manner of men; Though it be but a man's covenant, yet if it be confirmed, no man disannulleth, or addeth thereto.
I speak after the manner of men - I take an illustration from a human transaction of everyday occurrence. As faith is older than the law, so the law cannot set aside the promise.
But a man's covenant - whose purpose it is far less important to maintain.
If it be confirmed - when once ratified. No man disannulleth - `none setteth aside,' not even the author, much less any second party. 'None' who acts in common equity, much less the righteous God. The law is, by personification, regarded as a second person, distinct from, and subsequent to, the promise of God. The promise is everlasting, and more peculiarly belongs to God. The law is as something extraneous, subsequent, exceptional, and temporary (Galatians 3:17-19; Galatians 3:21-24.)
Addeth - none addeth new conditions, 'making' the covenant "of none effect" (Galatians 3:17). So legal Judaism could make no alteration in the fundamental relation between God and man, already established by the promises to Abraham; it could not add as a new condition the observance of the law, in which case the fulfillment of the promise would be attached to a condition impossible for man to perform. The "covenant" here is one of free grace-a promise afterward carried into effect in the Gospel.