This might not be the right forum to ask, but I couldn't think of a better one. If it is deemed unacceptable, I apologize in advance.
I was reading Luke the other day, and inspired by the curiosity to know the Greek and Latin equivalents of the word "leaven" that I found there (in the KJV), I took out my version of the Vulgate, and there I read:
12:1 multis autem turbis circumstantibus ita ut se invicem conculcarent coepit dicere ad discipulos suos adtendite a fermento Pharisaeorum quae est hypocrisis
which verse in the KJV reads as follows:
12:1 In the mean time, when there were gathered together an innumerable multitude of people, insomuch that they trode one upon another, he began to say unto his disciples first of all, Beware ye of the leaven of the Pharisees, which is hypocrisy.
My question concerns the relative pronoun: why is it quae rather than quod, the neuter? The text clearly suggests it should refer back to fermento, from fermentum which is neuter. It appears as if it has been made to correspond to the feminine noun hypocrisis.
So have I missed something in my Latin grammar lessons, and can it be the case that in a relative clause of the form "[X], which is Y", the grammatical gender of the pronoun "which" can be made to correspond to the gender of Y rather than that of X? If yes, I would greatly appreciate a reference to this fact in the literature.