Which Side Are You On? - Bible Study

In traditional Jewish fashion, John contrasts sin and righteousness, along with those aligned with either side (3:4-9). He then explains why the unrighteous oppose the righteous, appealing to a stock Jewish illustration for this principle: the righteous love one another, but the wicked, like Cain, hate the righteous (3:10-18). This was the test that would make clear who would ultimately triumph in the day of judgment (3:19-24). 

Greeks saw sin as imperfection; the Old Testament and Judaism saw it as transgression of God's law. John wants everyone to understand that he means sin in the biblical sense.