The angels, during their accusations, said: We will receive the Torah. God said to them: Isn't this the one at whose home you ate? For God had made Moses's form in the form of our father Abraham, may he rest in peace. He said: Aren't you ashamed before him? Then they were silent. It so resulted that by their having eaten at Abraham's home that the People of Israel received the Torah.
This is the reason that we hold a festive meal when a Torah scroll is brought, writing a Torah scroll is like receiving Torah at Sinai, and because Abraham, may he rest in peace, fed the angels, Israel received it.