Rabbi Yosef Mizrachi, who has become very popular with his internet lectures, tells the story of how he became a Baal Teshuva. It is based on the Rambam's details of the Torah's penal system.
The Torah enumerates four death penalties for various transgressions. There is stoning, burning by fire, decapitation, and strangulation. In addition, there is also Karet as well as מיתה בידי שמים, death at the hands of Heaven. There are also 207 cases of lashes in the Torah. And finally, there are monetary penalties for various sins such as stealing and rape and seduction.
Rabbi Mizrachi was confronted by a relative who asked how he could be so sure that the punishments in the Torah would not be implemented. Was he willing to risk that the Torah was outdated and these penalties did not apply any longer?
This made Rabbi Mizrachi think a great deal. He came to the conclusion that it was not worth taking such a risk. This was the single event that motivated him to return to Judaism and allowed him to become an extremely influential rabbi.
Reward and punishment is not something that we should take lightly. We need to wake up and more carefully observe the Torah and Mitzvot.