You, as a Bible apologist, should be able to believe any number of mutually contradictory ideas. For example, you should have no problem believing that the Old Testament is the unchanging word of God, and, at the same time, believe that the New Testament is the unchanging word of God. This seemingly impossible feat is easily accomplished.
Let us take the above as an example and look at each section in detail:
The Old Testament is the unchanging word of God.
This is obviously true. Since the Bible is the divine word of God, the Old Testament is literally and absolutely true. Therefore, all the stories, conclusions, and moral lessons of the Old Testament are still valid and are valuable and relevant for today.
The New Testament is the unchanging word of God.
This is obviously true. Since the Bible is the divine word of God, it is literally and absolutely true. Therefore, all the stories, conclusions, and moral lessons of the New Testament are valid and are valuable and relevant for today.
If anyone were to intimate that these two collections of stories are mutually exclusive and incoherent if viewed as one treatise on God, religion or morality, you can quite properly inform them that they are both true and do not contradict each other.
So to the ancient Hebrews, God was a angry cloud who demanded sacrifices and rituals and had myriad laws and statutes from which the slightest deviation could result in the deaths of thousands. To the early Christians, God was a transcendant being who required next to nothing but private prayer and actively worked to prevent the punishment of people who had committed moral crimes what would previously have required stoning. The glory of this step is that both of these are true... They are both accurate representations of one unchanging God.
This is true for any number of reasons. You could, for example, let them know that the important moral lessions and knowledge of God gathered from the literal stories have a deep dependence on the time, place, economy and culture where they originated. So, if viewed through the lens of those dependencies, both accounts point to the one overriding theme or something (Please see step six if the idea of culturally-dependent moral lessons sounds realistic). Or get creative: invent one of your own! A liberal application of step two will help greatly.
Step Four