A Cross logion on Hebrew

HARVARD MAGAZINE publishes an interesting inquiry from an alumnus:

Thomas Burrows hopes, after a half-century of searching, that someone can provide him with the source of the following assertion, delivered by Professor Frank Moore Cross during an elementary Hebrew course: “It was a saying of the ancient rabbis that you may as well learn Hebrew now because you will need it in the world to come.”

I was around Cross quite a bit for five years in the 1980s and I never heard him mention this particular saying. I do know that there is a Jewish tradition or saying that Hebrew is the language of heaven, but I don't have a specific reference. It does seem to be implied in the Talmud in b. Shabbat 12a, which advises making intercession for a sick person in Hebrew, because angels don't know Aramaic.