The Apostle had finished that grand paragraph (verses 21-26) which explains, in extenso, what it is that renders the Gospel "the power of God unto salvation." His explanation had been given, in brief, in chap. i. 17. But it was befitting to resume it, and expand it in the full affluence of its details.
The Apostle had evidently felt, in his own spirit, the intensest interest as he proceeded with the evolution of the details. Each item, as it turned up, seems to have sent a thrill through his heart. His ardour grew and glowed. He could not but admire the divine method of justification. Its symmetry, its completeness, its exquisite adaptations, and the might of the moral influences with which it was charged, charmed his soul. He stood arrested and rapt as he gazed. At length words came. And he utters forth, in abrupt and exceedingly condensed bolts of jubilant thought, some of the corollary-ideas which, in the midst of the consciousness of his ecstasy, he felt rising up with irrepressible and almost tumultuating energy within his mind. (Verses 27-31.) Foremost among these are references to the unbecoming feelings and incorrect notions, as regards the way of justification, that were unhappily characteristic of the great mass of his countrymen. And thus he says: -"Where then is the glorying? Shut out. By what kind of law? Of the works? Nay, but through the law of faith."
from pages 348-349, A Critical Exposition of the Third Chapter of Romans