1. The faith that we are defending must begin with, and necessarily include, the triune God— Father, Son, and Holy Spirit— who, as God, condescends to create and to redeem.
2. God's covenantal revelation is authoritative by virtue of what it is, and any covenantal, Christian apologetic will necessarily stand on and utilize that authority in order to defend Christianity.
3. It is the truth of God's revelation, together with the work of the Holy Spirit, that brings about a covenantal change from one who is in Adam to one who is in Christ.
4. Man (male and female) as image of God is in covenant with the triune God for eternity.
5. All people know the true God, and that knowledge entails covenantal obligations.
6. Those who are and remain in Adam suppress the truth that they know. Those who are in Christ see that truth for what it is.
7. There is an absolute, covenantal antithesis between Christian theism and any other, opposing position. Thus, Christianity is true and anything opposing it is false.
8. Suppression of the truth, like the depravity of sin, is total but not absolute. Thus, every unbelieving position will necessarily have within it ideas, concepts, notions, and the like that it has taken and wrenched from their true, Christian context.
9. The true, covenantal knowledge of God in man, together with God's universal mercy, allows for persuasion in apologetics.
10. Every fact and experience is what it is by virtue of the covenantal, all-controlling plan and purpose of God.
(K. Scott Oliphint, Covenantal Apologetics: Principles and Practice in Defense of Our Faith [Illinois: Crossway, 2013])
You can find Dr. Oliphint discussing covenantal apologetics at Reformed Forum here.
More apologetics posts:
Machen on the Perichoresis Between Evangelism and Apologetics
John Calvin's Influence on Reformed Apologetics
Van Til and the Perichoresis of Apologetics and Evangelism