The parallelism of the two arguments is marked by the repetition of the same conclusion in the same words in v. 17 and v. 20. 18. For I know that in me, (that is, in my flesh,) dwelleth no good thing.] For I know that there dwelleth not in me, that is in my flesh, any good. A proof of the reality of indwelling sin (v. 17) is furnished by experience of the absence of good: in a moral being, if good dwells not, sin must dwell (Lange). for to will is present with me.] It is essential to a just interpretation