Albert Barnes Commentary 1 John 3:21

"Beloved, if our heart condemn us not, we have boldness toward God;" — 1 John 3:21 (ASV)

Beloved, if our heart condemn us not. If we live in such a way as to have an approving conscience—that is, if we indulge in no secret sin; if we faithfully discharge every known duty; if we submit without murmuring to all the allotments of Divine Providence.

Then have we confidence toward God. Compare 1 John 3:19; 1 John 2:28; Acts 24:16.

The apostle evidently does not mean that we have confidence toward God on the ground of what we do, as if it were meritorious or as if it constituted a claim to his favor; but that we may live in such a way as to have evidence of personal piety, and that we may look forward with a confident hope that we shall be accepted by him in the great day. The word here rendered confidence—parrhsian—means properly boldness; usually boldness or openness in speaking our sentiments. See 1 John 2:28.

The confidence or boldness which we have towards our Maker is founded solely on the evidence that he will graciously accept us as pardoned sinners; not in the belief that we deserve his favor.