Chazal tell us (Avodah Zara 11a) that Unkelos, the nephew of the Roman Caesar, converted to Judaism. In a desperate attempt to get him to renege on his decision, his uncle sent a group of soldiers to forcibly bring Unkelos back to Rome. However, Unkelos piqued their interest by quoting some pesukim from the Torah, and thereby they were inspired to convert. The Caesar sent another group of soldiers, but this time with an explicit warning not to engage in any sort of conversation with Unkelos. As they led Unkelos away, he related that he had made an interesting observation. In an army, a private holds a torch to light the way for the lieutenant; the lieutenant holds the light for the captain, the captain for the general and the general for the king. "Does a king ever hold a torch to light the way for a common citizen?" he asked. The soldiers answered in the negative. "Well, our King," said Unkelos, "lights the way for Bnei Yisroel." As the pasuk states, "And Hashem walked in front of them in the form of a cloud by day, to show them the way, and at night in the form of fire to light the way for them." They too converted.
What was so powerful about the message that Unkelos conveyed that had the ability to sway those hardened soldiers? Rav Wolbe explains (Olam HaYedidus pg. 99) that Unkelos taught them something that gave them an entirely new perspective into the idea of religion and service of Hashem. From the ancient times down to this very day, people believe that they must honor G-d because at the end of the day life and death are in His hands, and a lack of honor could lead to dire consequences. Hence, they feel that religion is merely a means of demonstrating how they honor G-d. One honors G-d hoping that his actions will benefit him in the long run, similar to the reason one honors a king.
In Judaism, it is not the subject who lights the way for the King; rather, it is the King Himself who lights the way for his subjects. The Torah is not a means of honoring Hashem, rather, it is the torch that Hashem has handed us to light our way! Every mitzvah is a candle and the entire Torah is a light. This is not a poetic declaration; it is the reality of Torah for anyone who has toiled in its study and performed its precepts.
A mitzvah that is performed properly causes a radiance that can be felt. Whether it is a mitzvah that purifies our body (e.g. refraining from forbidden foods) or one that perfects our character traits (e.g. do not steal, swindle, gossip). There are mitzvos that illuminate our hearts with lofty feelings (e.g. tefillin, Shabbos, Yomim Tovim and the Days of Awe) and there are mitzvos that brighten our interpersonal relationships (e.g. the laws in Mishpatim). Each mitzvah is a torch that lights up our life with purpose and meaning. Furthermore, the light generated through Torah study is so great that it enters a person's mind and heart and opens them to an entirely different and meaningful outlook on life.
It is not for self-aggrandizement that Hashem asks us to serve Him. Rather, through the performance of mitzvos, it is He, Who is, so to speak, serving us by illuminating our lives. This is an idea that has the power to cause gentiles to convert. All the more so it has the ability to bring those who are already Jewish, closer to the Torah!
Good Yom Tov!