שכל העולם כולו כדאי הוא לו (אבות ו:א)

It is known from the holy Baal Shem Tov zt”l that when one learns Torah lishmah—for the sake of Hashem—their chidushei Torah (original Torah insights) are so powerful that those who hear them will be inspired to develop their own chidushim, and they too will begin to learn lishmah. From their chidushim, even more Torah innovations will emerge, and so on—an endless chain of Torah flowing from that original lishmah.

Therefore, it is said: שֶׁכׇּל הָעוֹלָם כֻּלוֹ כְּדַאי הוּא לוֹ—the entire world is worthwhile for him—because as long as the world exists, his chidushim will continue to bear fruit through his Torah lishmah.