# Of the Simple and Unchangeable Trinity explained — The City of God

> Chapter companion for The City of God by Augustine of Hippo.

## What happens

Augustine explores the nature of the simple and unchangeable Trinity—Father, Son, and Holy Spirit—as one God, arguing that in God alone substance and quality are identical, unlike created things which can lose what they have. He contrasts the simplicity of God with the composite nature of creatures, using analogies of light and air to illustrate how the soul is illumined by divine wisdom.

## Themes in this chapter

### True Worship and the One God

The chapter emphasizes the unique simplicity and unchangeability of the Triune God, contrasting with pagan polytheism and composite deities.

### Sin, Grace, and Redemption

Discusses the soul's darkness when deprived of wisdom, implying the need for redemption and restoration through participation in God's light.

## Character check-ins

### Augustine

Author and theologian, expounding on the simplicity of the Trinity and the nature of divine wisdom.

### Holy Scripture

Referenced as the source for calling the Spirit of wisdom 'manifold' and for the doctrine of the Trinity.

## Key lines

> things have a kind of likeness, which makes it suitable to say that the immaterial soul is illumined with the immaterial light of the simple wisdom of God, as the material air is irradiated with material light

The soul is enlightened by God's wisdom in a way analogous to how air is lit by physical light.

_Augustine uses the analogy of light and air to explain the soul's dependence on divine illumination._

> For God made nothing unwittingly; not even a human workman can be said to do so. But if He knew all that He made, He made only those things which He had known.

God created everything with full knowledge; nothing was made by accident.

_Highlights God's omniscience as the foundation of creation._

## Links

- HTML: https://www.betterreads.online/discover/the_city_of_god_se/chapters/part-ii-x
- Book: https://www.betterreads.online/discover/the_city_of_god_se
- All chapters: https://www.betterreads.online/discover/the_city_of_god_se/chapters