Today we come to the conclusion of John’s extended discourse on love as the mark of the believer that has occupied much of 1 John 3.
These verses are a bit difficult at first because of translation issues; thus, it is with the Greek grammar that we begin our discussion.
Though we do not have the space to discuss all the reasons, it is probably best to eliminate the “for” that stands at the beginning of verse 20 in the ESV. Modern commentators often translate the Greek this way and so do many modern translations, including the NIV and the NASB. When the “for” is removed, 1 John 3:19–20a reads, “By this we shall know that we are of the truth and reassure our heart before him whenever our heart condemns us.”
Removing the “for” is not critical for proper interpretation. However, when it is removed it becomes clearer that in this verse John assumes even mature believers at times will be troubled by their consciences and doubt their salvation. Thus, we should not be surprised if a crisis of assurance comes.
Removing the “for” also makes it clearer that when such crises occur, there are two ways in which we can regain our assurance. The first of these has us look back over our lives for evidence of love for other believers. In this case, the “by this” of verse 19 would have us reassure our hearts by finding specific instances where we have sacrificed to love our brothers.
Even as we do this, however, we will find on occasion that our hearts are troubled. We will see how far short of God’s requirements we remain, even if we have come a long way in our sanctification.
That is why verse 20b gives us the ultimate basis for our assurance: God Himself. God is indeed greater than our heart, and He knows everything, including the sins of which we remain unaware. Nevertheless, He still promises to receive us based not on our own goodness but on the righteousness of Christ imputed to us when we were born again. When our hearts condemn us, God’s promise to receive the repentant and humble person who trusts in Jesus alone (John 6:37–40) is the ultimate source of our assurance.
When it comes to our assurance (as well as everything else in life) we all must ask ourselves, “do I really trust God?” Trusting God is the first step towards assurance and drives us to do what John tells us Christians do. If we trust God we will affirm the incarnation, obey His commands, and love others. If you are having trouble trusting God, ask Him to renew your trust in Him. Make sure to seek out people in your life who will affirm His trustworthiness.