SIN NOT PRACTICED HERE
GracEmails usually avoid detailed talk about Greek words, but this particular assertion and the mindset behind it require an exception to the general rule. Beginning in 1962, I plowed through about eight years of undergraduate and graduate school classes in Koine, Hellenistic and Patristic Greek, and the main thing I discovered was how little I still knew. The more I studied, the more hesitant I grew of making sweeping generalizations based on the Greek.
In this case, my correspondent is certain but he is certainly mistaken. John himself sometimes use poieo to describe a regular practice or repeated act (John 5:27; 7:19; 1 John 3:22; 3 John 5, 10). On the other hand, New Testament writers sometimes use prasso to speak of a one-time deed (Lk. 22:23; 23:15; Acts 3:17; 5:35; 16:28; 19:36; 25:11, 25). John simply prefers the word poieo (153 of its 576 New Testament occurrences appear in John's writings). He uses prasso only twice (John 3:20; 5:29), and he never uses four other words formed off the same root.
At least once, both John (John 5:29) and Paul (Rom. 7:15) use poieo and prasso side by side to mean exactly the same thing. A Greek-English Lexicon of the New Testament and Other Christian Literature (Bauer-Arndt-Gingrich) begins its discussion of prasso with the statement that there is often no distinction between it and poieo. To know whether a passage refers to one-time action or repeated practice, we must consider context, verb tenses and other details. A vocabulary word alone does not usually justify a dogmatic conclusion. And now, grammar aside, let us not practice sin!