#15: What’s the Difference Between Knowing and Showing Christianity is True?

What’s the difference between knowing and showing Christianity is true?

I was first introduced to this helpful distinction by Christian philosopher William Lane Craig.

The Bible teaches that a believer knows Christianity is true on the basis of the internal witness of the Holy Spirit.

The Testimony of the Holy Spirit

Passages like Rom. 8:16 and Gal. 4:6 make this clear:

“The Spirit himself testifies with our spirit that we are God’s children.” – Romans 8:16

“Because you are his sons, God sent the Spirit of his Son into our hearts, the Spirit who calls out, “Abba, Father.” – Gal. 4:6

When we become a follower of Jesus, God’s Spirit then testifies to our spirit that we are His children.

In other words, God lets us know directly—without spoken or written words—that we belong to Him, that Jesus Christ has forgiven our sins, and that we have been reconciled to God.

This is a kind of rational testimony because the Holy Spirit is a person.

And this is how you know that Christianity is true.

Knowing vs Showing Distinction

Showing Christianity to be true involves giving reasons or evidence that are publicly available to everyone.

For example, a friend can take you at your word about your assurance that Christianity is true, but he can’t get inside of you to experience it for himself. The task of showing Christianity to be true is often called apologetics (see 1 Peter 3:15).

Knowing Christianity to be true is primarily for your own personal assurance (though this as part of your testimony can be a powerful way you can testify that Christianity is true).

Showing Christianity to be true is primarily for the benefit of others (though it does reinforce your confidence as well).

When Your Faith is Under Fire

Remembering the distinction between how you know vs. show Christianity to be true will better prepare you for times of doubt or when your faith is under fire.

I talk more about knowing vs showing your faith is true in Welcome to College.