The Defense of the Faith is a classic work by Cornelius Van Til. Van Til was born in Grootegast, the Netherlands in 1895. He lived until 1987. Van Til was a professor of apologetics at the Westminister Theological Seminary. He comes from a reformed view of theology. However, whether you are a reformed theologian or not, you will appreciate the work of Van Til in this defense of the faith.
In the first section of his book, Van Til gives the structure of his thought. He begins with a basic explanation of Christian Theology, taking on his presupposition of a reformed system of doctrine. Basic doctrines are addressed such as: the doctrine of God, the doctrine of man, the doctrine of Christ, the doctrine of salvation, the doctrine of the church, and the doctrine of last things.
Once a clear doctrinal statement is made we find the need to address the issue of how we get people interested in our faith. Van Til addresses this in his Christian philosophy of reality. Often times we as Christians tend to ignore the reality of those that are lost. We use Christian verbiage as if everyone should understand what we are talking about. This, of course, is not the reality. In order to win people to Christ, we must speak their language. Van Til points out the reality of the eternal triune God and the reality of sinful man. Sin has a curse. That curse keeps us from understanding God. Therefore, those who have yet to be freed from the curse will not comprehend our message unless we communicate to them in way that they will understand.
After looking at the Philosophy of Reality we then see a need to consider the Christian Philosophy of Knowledge. As Christians, we understand that all knowledge comes from knowing God. To know God, we must understand the Bible. The scriptures are the final standard of truth. In our defense of the faith, this cannot be ignored.
It is what we believe concerning our source of knowledge that then gives us the Christian Philosophy of Behavior. Because we believe the Bible to be the final standard of all truth, it therefore, becomes logical that we live according to that standard of truth. What we believe about God and who we are in Him will have a direct impact on how we conduct ourselves in this life. Christian ethics are far different than that of any other belief system. Every other belief system has a Summon Bonum that is centered on what man can achieve. The Christian Summon Bonum is centered on a relationship with Christ who alone is the means by which ultimate good is achieved. This ethical ideal is a gift from God. Man is taken out of the equation and all glory is given to God.
This is the underlining difference between the believer and the unbeliever. The unbeliever has no absolute authority or standard, therefore, his ethics is centered on himself. However, the believer does submit to an absolute authority, therefore, his way of living is centered on God. We can never fully present the Gospel to a lost world until we understand this fundamental difference between the believer and the unbeliever. To give a defense for the faith, we must understand where the unbeliever is coming from in comparison to what we know as the truth.