Why do ninth-century Hebrew documents agree with the Book of Abraham that it was God who taught Abraham astronomy?
In Abraham 3 it is God who teaches Abraham about the stars and the planets. Such as in verse 5:
And the Lord said unto me: The planet which is the lesser light, lesser than that which is to rule the day, even the night, is above or greater than that upon which thou standest in point of reckoning, for it moveth in order more slow; this is in order because it standeth above the earth upon which thou standest, therefore the reckoning of its time is not so many as to its number of days, and of months, and of years.
Jeff Lindsay notes how this is attested in ancient documents such as:
Where would Joseph have learned this specific part of Abraham’s story?