I heard that Hashem offered the Torah to all the Gentile nations but they didn’t accept. Where do we know that from? Is it really true?
The answer is that it’s a Sifri. The Sifri says, “Hashem mi’Sinai ba, vi’zarach mei’Seir lamo, ho’fee’ah mei’har Paran.” [Vi’zos Ha’bracha 33-2] Hashem went to Seir and to Paran and He offered them the Torah and they said, “Mah kasuv bah?” What’s written there? It’s as if they said, “What’s written there?” That’s how Chazal explain, “ho’fee’ah mei’har Paran.”
Now, we understand it as follows. When Hashem gave the Torah at Har Sinai and He saw how the Am Yisroel accepted it with such a remarkable and unlimited enthusiasm, He said, “Mee yee’tein, vi’haya li’vavam zeh, li’yirah oi’see kol ha’yamim.” So Hashem said, “Look at the Am Yisroel! Would any other nation have done that?!” So He compared us to the other nations and said, “Suppose I would have offered the Torah to Seir or to Paran. Would they have accepted it like the Am Yisroel? Of course not. And really, Hakodosh Boruch Hu did offer it to them. He always sent them good men to teach them. There were always chasidei umos ha’olam, talmidim of Avraham Avinu. The nations had many opportunities to hear good things. But did they yearn for the good things? Did they show a willingness to make progress? No! They weren’t interested. So what would be the purpose of going any further with them?
And therefore it’s as if Hashem offered them the Torah and they said, “no.” They answered “No” to the great men who spoke to them beforehand. They all heard about Avraham Avinu. The Rambam says that Avraham Avinu had tens of thousands of students who came to listen to him. And these talmidim went out and taught the nations the teachings of Avraham Avinu.
And therefore the nations that showed that they weren’t interested in the teachings of Avraham Avinu, why should they accept the teachings of Hakodosh Boruch Hu? And so Hashem said that it’s the same as if I had offered them the Torah and they said, “Mah kasuv bah?”