This video has 3 parts, as well as questions and answers in individual clips.

For those who cannot watch the video, you can read this essay by Dr. Craig which covers exactly the same ground as the video. The essay is for Christians already familiar with basic apologetics.

Part 1 of 3:

Part 2 of 3:

Part 2 of 3:

Here’s a quick couple of quotes from the essay for those who cannot watch:

If there is no God, then any ground for regarding the herd morality evolved by homo sapiens as objectively true seems to have been removed. After all, what is so special about human beings? They are just accidental by-products of nature which have evolved relatively recently on an infinitesimal speck of dust lost somewhere in a hostile and mindless universe and which are doomed to perish individually and collectively in a relatively short time. Some action, say, incest, may not be biologically or socially advantageous and so in the course of human evolution has become taboo; but there is on the atheistic view nothing really wrong about committing incest. If, as Kurtz states, “The moral principles that govern our behavior are rooted in habit and custom, feeling and fashion,”⁵ then the non-conformist who chooses to flout the herd morality is doing nothing more serious than acting unfashionably.

The objective worthlessness of human beings on a naturalistic world view is underscored by two implications of that world view: materialism and determinism. Naturalists are typically materialists or physicalists, who regard man as a purely animal organism. But if man has no immaterial aspect to his being (call it soul or mind or what have you), then he is not qualitatively different from other animal species. For him to regard human morality as objective is to fall into the trap of specie-ism. On a materialistic anthropology there is no reason to think that human beings are objectively more valuable than rats. Secondly, if there is no mind distinct from the brain, then everything we think and do is determined by the input of our five senses and our genetic make-up. There is no personal agent who freely decides to do something. But without freedom, none of our choices is morally significant. They are like the jerks of a puppet’s limbs, controlled by the strings of sensory input and physical constitution. And what moral value does a puppet or its movements have?

[…]Moreover, if atheism is true, there is no moral accountability for one’s actions. Even if there were objective moral values and duties under naturalism, they are irrelevant because there is no moral accountability. If life ends at the grave, it makes no difference whether one lives as a Stalin or as a saint. As the Russian writer Fyodor Dostoyevsky rightly said: “If there is no immortality, then all things are permitted.”

If you want a much shorter, slicker version of this argument to share, Reasonable Faith has produced this nice 5-minute video that you can tweet or share on your Facebook page or whatever:

The moral argument is the easiest argument in the world to discuss with non-Christians, as everyone has to have an answer to questions like “what makes humans valuable?” and “why should I do the right thing when it goes against my self-interest?” and “will evildoers who escape justice in this life be punished when they die?” and “do humans have free will to make moral choices?” These are interesting questions, and people can just give their opinion and then think about it as they discuss it.

You can read a debate transcript where Dr. Craig puts his ideas to the test, against Dr. Richard Taylor. I found this debate very helpful for answering the question that everyone should be able to answer: “why should I be moral?”