What does 1 John 3:19 mean?

This verse offers the first part of a statement which continues through the next verse. The opening of John's sentence offers two insights. First, what John is about to say, in verse 20, will help a believer know he or she is acting according to the truth of the gospel. Second, his statement will provide reassurance to the believer's heart, in those times when we feel conviction of sin.

First John 5:13 will provide a summary statement regarding a person's ability to know, for certain, that they are a believer in Christ. This particular verse, 1 John 3:19, reassures believers: when they act in love, it is proof that they are "abiding" in the life that Christ wants for us (John 10:10).

The concept of reassurance is also tied to verse 20, which explains how Christians ought to respond to conviction of sin. Rather than seeing conviction as a reason to despair, saved believers can rest assured that God will forgive us (1 John 2:1).