In Classical Apologetics (CA), a person is first going to attempt to establish the existence of God using ontological, teleological, cosmological, or moral arguments. For example, revealing the design of the universe, how everything created needs a first cause, or where we get morality from can all fall underneath the umbrella of CA. In essence, what CA attempts to do is first establish a foundation by which we can base our philosophical assumptions in order to prove the validity, or truth, of events such as the resurrection of Jesus Christ. Because if there is a God and He made the universe, and has authored the natural laws and is allowed to bend or break those laws, it would be rational to presume that the resurrection from the dead, or any miracles, is plausible if not a reality.
After the existence of God can be established or agreed upon, another component of CA is to affirm the historical validity of the Bible, the veracity of fulfilled prophecies, and the bodily resurrection of Jesus Christ (this being one of the central themes to CA). This is so that, apologetically, we can distinguish the uniqueness of Christianity from other theistic religions, as well as the validity and truth of the Scriptures. In short, CA appeals to the unbeliever’s reason as well as rationality to prove the testimony of Scripture as being true.
What a typical CA argument looks like is when someone predictably attempts to refute the existence of God simply because Hell is a place of eternal “cruelty.” In this case, using God’s law, the Ten Commandments, as a tool to help them understand why God must cast sinners into Hell would be an appeal to their reason (and even their conscience). If they rebuttal with, “God doesn’t exist anyway, therefore there is no right or wrong,” then you would most likely appeal to how morality reveals that God does indeed exist, and then proceed to explain why. In this short scenario, it is important to grasp that CA-type arguments are attempting to establish to the sinner that the God of the Bible does indeed exist, and it appeals to rational thought, conscience, or philosophical arguments as a means to provoke the unbeliever to think about what they very often do not take the time out themselves to think about – God.