If every person was granted the potential to change worldly events in a positive direction, and even to introduce a novelty, this is surely true of the Jewish nation. Its very existence is a deviation from the order of the world, and it has been assigned with the role of serving as “A light unto the nations (Yeshaya 42:6).”There are plenty of very smart, well-educated, and even refined people in the world who search and strive for truth and morality. Yet all around us, we see moral confusion, and in particular the philosophy of moral relativism, the idea that there does not and cannot exist any one absolute truth, universal morality, or grand purpose to the cosmos. Rather, there are many opinions on these matters, all equally valid and equally irrelevant in daily life.
Since this description is given by our Torah, “a Torah of truth (Blessings on the Torah)” it is exact in all its details. This includes the fact that light represents a force that, although apparently not introducing any novelty, displays and reveals the true nature of the object [being illuminated]. Usually, this light is essential to discern between good and evil, holiness and impurity, health and sickness, and between those who call evil, good, and sickness, health.
Nitzutzei Ohr, p. 83.
How can such smart people fail so miserably? Because they lack the tools of discernment that Hashem gave us. No matter how hard they try, they are not able to truly discern between right and wrong, truth from falsehood. They can get it right some of the time, but never all of the time. This is an ability that has been granted to the Jewish people alone, through the teachings of the Torah. Since it is the wisdom of Hashem, Who is the G–d of Truth, it alone is the repository of absolute Truth.
When we are truly aware of the sublime gift that we have been given, we will go out and humbly but confidently share it with Jews who are not yet aware of its true nature, by teaching them how to fulfil their obligations as Jews, and with non-Jews, by teaching them how to serve Hashem according to the Noahide laws.