The key grammatical questions are these: (1) to what does by this refer? (2) Does the verb peisomen mean assure or persuade? In my judgment, and by this in 3:19 is a thematic reference to 3:16–18, which is also continued in verses 23–24. In verse 19 John addresses a crucial question: How do we know we are from the truth or belong to God? In verses 16–18 he argues that practical expressions of love, first in Christ’s death and then in one’s economic sharing, are evidence of belonging to God. He takes