Purifying the heart
Nor does faith fulfill either the negative or the positive law as to the external part only; but it works inwardly by love (Galatians 5:6) to the purifying of the heart, cleansing it from all vile affections. Everyone who has this faith in him purifies himself even as he is pure (1 John 3:3): purifies himself from every earthly, sensual desire, from all vile and inordinate affections — yes, from the whole of that carnal mind which is enmity against God (Romans 8:7). At the same time, if it has its perfect work, it fills him with all goodness, righteousness, and truth (Ephesians 5:9). It brings all heaven into his soul and causes him to walk in the light even as God is in the light (1 John 1:7).
1771 text
4. Nor does faith fulfil either the negative or positive law, as to the external part only: but it works inwardly by love, to the purifying of the heart, the cleansing it from all vile affections. Every one that hath this faith in him purifieth himself even as he is pure: purifieth himself from every earthly, sensual desire, from all vile and inordinate affections: yea, from the whole of that carnal mind, which is enmity against God. At the same time, if it have its perfect work, it fills him with all goodness, righteousness and truth. It brings all heaven into his soul, and causes him to walk in the light even as God is in the light.