3:21 {21} Beloved, if our heart condemn us not, [then] have we confidence toward God.
(21) A third effect also rises from the former, that in these miseries we are sure to be heard, because we are the sons of God: as we understand by the grace of sanctification which is only for the elect.
3:21 If our heart condemn us not, [then] have we confidence toward God. Then we have a conscience void of offense before God and are assured that he will hear us.
3:21 If our heart condemn us not - If our conscience, duly enlightened by the word and Spirit of God, and comparing all our thoughts, words, and works with that word, pronounce that they agree therewith. Then have we confidence toward God - Not only our consciousness of his favour continues and increases, but we have a full persuasion, that whatsoever we ask we shall receive of him.
3:16-21 Here is the condescension, the miracle, the mystery of Divine love, that God would redeem the church with his own blood. Surely we should love those whom God has loved, and so loved. The Holy Spirit, grieved at selfishness, will leave the selfish heart without comfort, and full of darkness and terror. By what can it be known that a man has a true sense of the love of Christ for perishing sinners, or that the love of God has been planted in his heart by the Holy Spirit, if the love of the world and its good overcomes the feelings of compassion to a perishing brother? Every instance of this selfishness must weaken the evidences of a man's conversion; when habitual and allowed, it must decide against him. If conscience condemn us in known sin, or the neglect of known duty, God does so too. Let conscience therefore be well-informed, be heard, and diligently attended to.