50. It can be seen from this what the nature of a spiritual faith is and the nature of a faith not spiritual: that a spiritual faith is found in people who refrain from sinning, for people who refrain from sinning do good, not of themselves, but from the Lord, as may be seen in nos. 18-21 above. And through their faith they become spiritual. Faith in their case is the truth.

This the Lord teaches in John:

This is the judgment, that the light came into the world, but men loved darkness more than the light, because their deeds were evil. For everyone who does evil hates the light and does not come to the light, lest his deeds be exposed. But he who does the truth comes to the light, that his deeds may be clearly seen, since they have been done in God. (John 3:19-21)