Augustine wrote “On the Trinity” partly to guide readers in their knowledge of God. In this pursuit, he self-consciously followed dominical sayings such as, “And this is eternal life, that they know you, the only true God, and Jesus Christ whom you have sent” (John 17:3).

One key term that defines this journey is purify. Augustine believes that we need to purify our minds “because the weak eye of the human mind cannot be fixed on a light so dazzling, unless it has been nourished and become stronger by the justice of faith” (Aug., De Trin. 1.2.4).

To purify the mind, Augustine has something quite concrete in mind that follows the order of teaching contained within Scripture itself. As he says, “we must first find out by an appeal to the authority of the Sacred Scriptures whether faith is in a position to do so [i.e., reveal God to us]” (De Trin. 1.2.4).

Ultimately, his answer will be a qualified yes, provided “By [the principles of faith] a carefully-regulated piety,” heals our minds so we can “perceive the unchangeable truth” (De Trin. 1.2.4). In other words, Augustine’s ascent to God means that our whole self comes to know God.

How does he suggest we go about our pursuit of true knowledge of God?

First, it all begins with the faith once for all handed down to the saints. And that faith centers on inseparable operations, namely, that the Father, Son, and Spirit work inseparably in all that they do. Augustine emphasizes the unity of divine action—what later theology would call the principle that opera trinitatis ad extra sunt indivisa (the external works of the Trinity are undivided). 

But the key point is: The one Lord Jesus Christ, the one God and Father of all, and the one Spirit of God inseparably operate in all they do, which evinces their unity of power, of substance, and ultimately their equality.

Second, by embracing this faith taught by the apostles and preserved in the church, we can purify our minds as we pursue a knowledge of God in Holy Scripture.

Third, Augustine lays out a pathway through the Old to the New Testament to know God in accordance with an order of teaching that moves from visible signs to invisible realities.

What is Augustine’s pathway?

Augustine begins with God’s revelation in the Old Testament through angels or other creatures (e.g., prophets). He then moves to the unique way that Christ and the Spirit are sent from God in their two visible missions—the Incarnation and Pentecost.

Next, Augustine reflects on how the visible missions of the Son and Spirit reveal eternal realities, namely, that both proceed from the Father as their origin or source. And lastly, Augustine thinks we can reflect on our inner man (our memory, understanding, and will) because we are created in God’s image and our inner man has an analogical relation to God who is invisible, immortal, and simple.

Put in bullet point form, these steps are:

• To know God in his manifestations or theophanies through his creatures within the Old Testament. The invisible God uses visible angels or creatures to reveal his will (operations) 
• To know God in Christ at the Incarnation, which means the invisible Son of God becomes visible; and to know the Holy Spirit who uniquely dwells within us at Pentecost (missions)
• To know God in Christ and the Spirit, who proceed eternally from the Father (processions)
• To know God in whose image we are made by reflecting on the parallels between God’s inner processional life and our inner life (psychological analogy)

In other words, we move from the Old to the New Testaments to understand what the Bible says about God. We reflect on how operations and missions tell us about God’s processional or inner life. And we find parallels in God’s created order by looking at our inner man.

As Augustine models his ascent to God, we can see how his ascent is really the ascent of every human being. We begin by seeking God’s face in Holy Scripture, and through it, we come to know “the only true God, and Jesus Christ whom you have sent” (John 17:3). 

A lot more could be said, but I wanted to share this basic sketch. A lot more details are needed to fill in the picture. And I plan to fill those details in a course at the Davenant Hall, which I am teaching this Summer. You can still register by clicking here!