romans 7:13 Was then that which is good made death unto me? God forbid. But sin, that it might appear sin, working death in me by that which is good; that sin by the commandment might become exceeding sinful. - Free Bible Online

      13. Was then that which is good made--"Hath then that which is good become"
      death unto me? God forbid--that is, "Does the blame of my death lie with the good law? Away with such a thought."
      But sin--became death unto me, to the end.
      that it might appear sin--that it might be seen in its true light.
      working death in--rather, "to"
      me by that which is good, that sin by the commandment might become exceeding sinful--"that its enormous turpitude might stand out to view, through its turning God's holy, just, and good law into a provocative to the very things which is forbids." So much for the law in relation to the unregenerate, of whom the apostle takes himself as the example; first, in his ignorant, self-satisfied condition; next, under humbling discoveries of his inability to keep the law, through inward contrariety to it; finally, as self-condemned, and already, in law, a dead man. Some inquire to what period of his recorded history these circumstances relate. But there is no reason to think they were wrought into such conscious and explicit discovery at any period of his history before he "met the Lord in the way"; and though, "amidst the multitude of his thoughts within him" during his memorable three day's blindness immediately after that, such views of the law and of himself would doubtless be tossed up and down till they took shape much as they are here described (see on Ac 9:9) we regard this whole description of his inward struggles and progress rather as the finished result of all his past recollections and subsequent reflections on his unregenerate state, which he throws into historical form only for greater vividness. But now the apostle proceeds to repel false inferences regarding the law, secondly: Ro 7:14-25, in the case of the REGENERATE; taking himself here also as the example.

JFB.