Jamieson, Fausset and Brown on Romans 6:19

19. I speak after the manner of men--descending, for illustration, to the level of common affairs.

because of the infirmity of your flesh--the weakness of your spiritual apprehension.

for as ye have yielded--"as ye yielded," the thing being viewed as now past.

your members servants to Uncleanness and to Iniquity unto--the practice of

iniquity; even so now yield your members servants to Righteousness unto holiness--rather, "unto (the attainment of) sanctification," as the same word is rendered in 2Th 2:13; 1Co 1:30; 1Pe 1:2:--that is, "Looking back upon the heartiness with which ye served Sin, and the lengths ye went to be stimulated now to like zeal and like exuberance in the service of a better Master."