Introduction to Christianity 101: Practical Theology

“We demolish arguments and every pretension that sets itself up against the knowledge of God, and we take captive every thought to make it obedient to Christ” (2Cor 10:5).

The first section of our introduction to Christianity is what I’ll call practical theology. Theology is simply thinking about God. Everyone is a theologian. Everyone has an idea of what they think God is like, and that affects how they live. So it’s important to have correct ideas about God. As Tozer said, “What comes into our minds when we think about God is the most important thing about us.”

But not all theology is equally important. Every discipline has specialists. They get into academic discussions that don’t matter to the average person. They drill down deep and explore the frontiers. They split hairs and parse terms. We don’t necessarily need to know all of that. It's important to know what God is like, what’s wrong with people, and how we’re saved. It's less important to know how many angels can dance on the head of a pin, exactly how election works, or whether the millennium is literal or figurative.

Which is why I call this “practical” theology. I want to focus on what we absolutely need to believe, why we believe it, and what difference it should make in our lives. And knowing God — and what he says about things — more deeply will help us love him more dearly and see things more clearly. And it will help us to explain what we believe and why we believe it to others.

All of this is necessary because there are a lot of bad ideas about God out there. Everyone's a theologian, and most people are bad ones. They have wrong ideas about God, wrong ideas about humanity, and wrong ideas about what’s wrong with the world and how to fix it. And they can influence us if we’re not careful. But we can also influence them!

All of this is about making a difference in the world for Christ and his kingdom. We do not want to know things for the sake of knowing things. “Knowledge puffs up” (1 Cor 8:1) unless we are careful to guard our hearts against pride. We only know what we know because God has chosen to reveal it, and when he revealed it he gave us a task. We want to be more like Jesus and to take the good news to the people who desperately need to hear it.

To that end, we will focus on a very particular subset of Christian theology. Theology is sometimes divided into (1) primary issues, (2) secondary issues, and (3) tertiary issues (see diagram above). Primary issues include those things you must believe to be saved and those things that make us distinctly Christian (eg, the trinity). All Christians should believe these things. Secondary issues are things that determine whether we can belong to the same congregation (eg, infant vs believer baptism). Tertiary issues are things that people within the same church can disagree on (eg, views of the end times). I intend, to the best of my ability, to stick to primary issues. If I discuss secondary issues, they will be clearly labeled as such.

I want to do it this way because I don’t want to talk about being a good Baptist or a good Presbyterian (not that there’s anything wrong with being either of those things) but about what all Christians have in common, what makes us one family and one people with one mission: to introduce the lost to Jesus.

So this will be organized around the Apostles' Creed, the ancient summary of what all Christians everywhere ought to believe.

I believe in God the Father, Almighty, Maker of heaven and earth,

And in Jesus Christ, his only begotten Son, our Lord,
Who was conceived by the Holy Spirit, born of the Virgin Mary,
Suffered under Pontius Pilate, was crucified, died and buried.
He descended into hell. The third day he rose again from the dead.
He ascended into heaven, and sits at the right hand of God the Father Almighty
From thence he shall come to judge the quick and the dead.

I believe in the Holy Spirit,
The holy catholic Church,
The communion of saints,
The forgiveness of sins,
The resurrection of the body,
And the life everlasting. Amen.