It is very much part of Torah Mi’Sinai. You’ll see all over Torah Shebichsav uses of nouns in either masculine or feminine. Some nouns have dual forms, as Rashi al haTorah points out (is it in Chayei Soroh? Can’t remember).
It is very much part of Torah Mi’Sinai. You’ll see all over Torah Shebichsav uses of nouns in either masculine or feminine. Some nouns have dual forms, as Rashi al haTorah points out (is it in Chayei Soroh? Can’t remember).