Our sages pondered this question, and their answers, preserved in Kohelet Rabbah, are surprisingly insightful.
The verse in question is from Ecclesiastes (8:1): “Who is like the wise man? And who knows the interpretation of a thing? A man’s wisdom makes his face shine…” So, who exactly is this wise man? According to Kohelet Rabbah, it's the Torah scholar. The one who doesn't just know the law, but understands its nuances, who "knows how to interpret his learning," and "knows how to arrive at halakhic (Jewish legal) conclusions." : haven't you seen that "light" in someone deeply engaged in study, wrestling with a difficult text, and then finally... aha! ...understanding dawns. Kohelet Rabbah suggests that this intellectual and spiritual effort actually changes a person, illuminating their face.
But what happens when the scholar doesn't know the answer? Kohelet Rabbah continues, "The wisdom of a man illuminates his face when he is asked a question and responds; and the boldness of his face is changed when he is asked a question and does not know how to respond.” It's a very human picture, isn't it? We see the joy of knowledge, but also the vulnerability of uncertainty.
The text illustrates this with a story about Rabbi Ḥiyya. He was teaching about the laws of the firstborn animal (bechor) – a complex subject! – and the text notes that the face of Bar Pedaya "glowed" because he understood what Rabbi Ḥiyya was saying. Rabbi Ḥiyya immediately recognized this, saying, "This one knows what I am sitting and teaching." It’s that visible spark of understanding we’re talking about.
Then there's the story of Rabbi Yehuda ben Rabbi Ilai. A gentile, seeing Rabbi Yehuda's radiant face, assumed he must be indulging in vices: either drunk, lending money at interest, or raising pigs (all activities frowned upon or forbidden to Jews). Rabbi Yehuda vehemently denied these accusations, explaining that his glow came from his Torah study. He quotes the verse: “The wisdom of a man illuminates his face…”
It's fascinating how easily others can misinterpret that inner light, isn't it? They see the radiance, but assume it must come from something external, often something negative. But Rabbi Yehuda knew the true source: the profound connection to Torah.
Another anecdote involves Rabbi Abbahu. He returned from Caesarea with a glowing face, prompting his students to speculate that he had found a treasure. But Rabbi Yoḥanan, his teacher, wisely suggested that perhaps he had simply heard some new Torah. Sure enough, Rabbi Abbahu had encountered an ancient Tosefta (a collection of Jewish legal traditions), and that was the source of his radiance.
Again, the verse is quoted: “The wisdom of a man illuminates his face…”
These stories, found in Kohelet Rabbah, invite us to consider what truly makes us shine. Is it external achievements? Material wealth? Or is it something deeper, something connected to knowledge, understanding, and a connection to something greater than ourselves? Perhaps, just perhaps, the secret to a radiant face lies not in what we possess, but in what we learn and how we connect to the wisdom of the ages.