Ἐν ᾧ ἔχομεν τὴν ἀπολύτρωσιν διὰ τοῦ αἵματος αὐτοῦ, τὴν ἄφεσιν τῶν παραπτωμάτων, κατὰ τὸ πλοῦτος τῆς χάριτος αὐτοῦ
At first I thought nothing of this construction until I remembered that πλοῦτος is masculine and should have a masculine article, and I'm stuck trying to figure out what the neuter article's purpose and meaning is here.
I was wondering if Paul might have merely switched this article to the other side of κατὰ, where the article would be functioning like a relative pronoun (τὸ κατὰ πλοῦτος = "which is according to the richness...). But the previous clause has two parallel but distinct ideas that the article could be referring to, it doesn't make sense for the article to be referring to only one of the ideas, yet the article is singular. But as seems to often be the case with the neuter gender, could a singular neuter article (functioning as a relative pronoun) have a plural antecedent?
If the article isn't referring to a clause or train of thought, the only neuter antecedent I see is τοῦ αἵματος, but that seems like an odd antecedent giving the context to me.