חָּכָּם ו נָּבוֹן הַגּוֹי הַגָּּדוֹל הַזֶה-הַחֻקִים הָּאֵלֶה ו אָּמ רוּ רַק עַם-ת כָּלש מַר תֶם וַעֲשִיתֶם כִי הִוא חָּכ מַת כֶם וּבִינַת כֶם ל עֵינֵי הָּעַמִים אֲשֶר יִש מ עוּן אֵ וּ (דברים ד,ו)
Observe therefore and do them; for this is your wisdom and your understanding in the sight of the peoples that, when they hear all these statutes, shall say: 'Surely this great nation is a wise and understanding people.'
Shabbos 75a: (R. Shimon ben Pazi): It says about one who knows how to calculate Tekufos and Mazalos, but does not, "v'Es Po'al Hash-m Lo Yabitu u'Ma'aseh Yadav Lo Ra'u."
(R. Shmuel bar Nachmani): It is a Mitzvah to calculate Tekufos and Mazalos from the above verse. What is the wisdom and understanding which we display in front of the nations? It is calculating the planetary movements.
The Gemara tells us that we are not allowed “to speak to or about” someone who knows how to calculate the seasons and astronomical movements, but neglects to involve himself in these matters. This ban against speaking with someone seems strange. What has the person done that is so terribly wrong to deserve being an outcast?
The sefer Panim Yafos writes (Parashas Va’eschanan) that the movements of the stars and other heavenly bodies comprise a beautiful array of praises of Hashem and glory of His dominion. Anyone who has the ability to unlock these cosmic secrets and to inform the world about the majesty of Hashem’s infinite powers has the key to inspire and uplift those around him. If he fails to spread the honor of Hashem, then, measure for measure, his own prominence should also be diminished by us refusing to talk to him or about him.
Torah Temimah (Devarim 4,6) writes that the calculations of the movements of the planets is something that has always awed the world. Many nations have been so overwhelmed by the grandeur of the heavens that they have created a culture of idol worship based upon it. If someone could show clearly that the planetary and other movements are predictable, this would show that they are not god-driven but are actually part of the nature of Creation itself. By calculating eclipses and arrivals of comets and solar events, we can show these idolaters that there is no significance to the pagan beliefs. Sefarno on this verse tells us that “our wisdom to the nations” is our ability to answer the scoffers and non-believers. This explanation also appears in the comments of the Ran to our Gemara.
Accordingly, someone who can respond to those who worship the stars by using this information to dispel their errors is obliged to do so in order to increase the glory of Hashem. If the person does not care to use his knowledge and to fulfill this objective, we cannot praise him for his knowledge, for he has refused to use it properly.
The commentators seem to classify the studying of the Heavens into three categories:
- Laws of Kiddush haChodesh - the calculations for the calendar systems. This is a part of Talmud Torah.
- Astronomy - studying the course of the planets and stars in their orbit. This seems to be the matter in this Gemara. These matters are studied to assist in our appreciation and understanding of the Creator. However, these matters are not to be studied under a disreputable teacher.
- Astrology - studying the influence that heavenly bodies exert over human affairs. The Ramban states that no mitzvah exists to study Astrology. However, one who is knowledgeable in these matters is obligated to use these skills to bring honor to HaShem.
