In my last column, I suggested a number of reasons for the rise of Orthodox Judaism and the decline in membership among non-Orthodox denominations.

In this column, I would like to discuss one important reason that often goes unnoted.

That reason is faith — not only faith in God, but specifically faith that the Torah represents the word of God.

“Represents the word of God” does not necessarily mean that God dictated every word to Moses. Nor does it necessarily imply any specific form of divine communication. How the Torah came to be is an entirely different question from whether it ultimately comes from God.

Having taught the Torah much of my life, I am well aware that there are challenging, even difficult, parts of the Torah. However, in almost every case, with intellectual honesty coupled with a belief in the divinity of the Torah, those difficulties can be surmounted.

Take the often-cited example of the law demanding that a son who will not listen to either his father or mother and who is “a stubborn and rebellious glutton and drunk” be stoned.

As it turns out, this law was one of the most morally elevating laws in mankind’s history. By stipulating that the son must be taken to a court and that only the court can execute him, and that the son had to revile both his mother and father, the law permanently took away the right of a father to kill his child.

This was likely a first in human history. Throughout the world, as in the Code of Hammurabi, children were the property of their father — who was, therefore, allowed to kill his child. The Torah law ended that. Moreover, it is unlikely that one son in Jewish history was ever stoned by a Jewish court. On the contrary, thanks to the Torah, Jewish family life was the most peaceful in every society in which Jews lived. Would that those who in believe in “honor killings” today had inherited such a law in their holy works.

Whatever the difficulties moderns may have with believing that the Torah is divine, the difficulties with believing that the Torah is just a creation of men are far greater.

Of course, many Jews who don’t believe in the divinity of the Torah — or even in the God of the Torah — feel Jewish and some are deeply devoted to the Jewish people. Indeed, it was secular Jews, not Orthodox Jews, who founded Israel. But over the course of a few generations, without belief in the God of the Torah and in the Torah coming from God, most Jews will gradually leave Judaism and eventually the Jewish people.

Take Shabbat observance as an example. There are excellent rational, non-God-based reasons to observe the Shabbat. But the reason the vast majority of Jews who do not work on Shabbat (or on the Torah’s other holy days) refrain from work is that we believe God commanded us to. Over a few generations, those who believe that men wrote the commandment to observe the Shabbat will eventually abandon it. But those who believe that God gave the commandment will not.

Similarly, if one does not believe that the Jews were slaves in Egypt, let alone that God took the Jews out of Egypt, one can be a committed Jew and even celebrate Passover. But over time it strains credulity to believe that generation after generation of Jews will celebrate an event they don’t believe ever happened. They may celebrate family time together at a seder, but not Judaism.

The centrality of belief in a God-given Torah obviously challenges most non-Orthodox Jews. But it should also challenge many Orthodox Jews.

Many Orthodox Jews think that observance of halachah, more than faith, is what ensures Jewish survival. Every yeshiva student is taught the famous line from the Midrash: “It would be better that the Jews abandoned Me [God] but kept my commandments.”

But Conservative Judaism provides a nearly perfect refutation of this idea. Many Conservative rabbis in the past, and many today, have led thoroughly halachic lives, virtually indistinguishable from many modern Orthodox rabbis. If halachah is what keeps Jews alive, the Conservative movement should not be in decline — and it should certainly attract more Jews than Reform, the least halachic of the major denominations.

Furthermore, if halachah is the single most important thing to the Orthodox, why has Orthodoxy been so opposed to Conservative Judaism and to Conservative rabbis who have been scrupulously halachic? The answer is that the Conservative movement dropped belief in a God-given Torah. (Jewish Theological Seminary Web site: “The Torah is the foundation text of Judaism … not because it is divine, but because it is sacred, that is, adopted by the Jewish people as its spiritual font.”) And it is that, not lesser observance of halachah, that is the primary reason for Conservative Judaism’s decline.

Judaism cannot just be a commitment to the Jewish people, love of Israel or even just ritual observance. As important as each is, none will ensure Jewish survival as much as belief — belief in the God of the Torah and in the Torah of God.

Dennis Prager is a nationally syndicated radio talk-show host (AM 870 in Los Angeles) and founder of PragerUniversity.com. His latest book is the New York Times best seller “Still the Best Hope: Why the World Needs American Values to Triumph” (HarperCollins, 2012).