There’s a principle, revealed in the Bible, that we learn to understand the reason for an action by doing it (Ps. 111:10b). People without this realization can easily fall for the old nonsense that morality is arbitrary. It’s the idea of relativism: there is no moral authority --- no moral absolutes.
You do not need the Bible to figure out the fallacy that such a conjecture is. You just need to examine morality in various species. Among humans, there are some traits that are universally virtues and others that are everywhere despised. For example, show me a culture where cowardice is regarded as a virtue. There are certain things that no culture would suffer to be done to its little children.
Then, look at other species. Rats will only play with rats that play according to the rules. Dogs have a moral code, and bad dogs are shunned. Chimps like to know who the good chimps and the bad chimps are.
Morality develops according to the needs of the species. In many cases, rules are laid down to describe what is already happening in the healthy interactions. Cult members would do well to realize the foregoing principle. If a rule seems to have nothing to do with benefitting the population expected to keep it, then God is not likely behind it. Nor has it been developed as a description of healthy behavior.