Truth needs to be sought, found and expressed within the "economy" of charity, but charity in its turn needs to be understood, confirmed and practiced in the light of truth. In this way, not only do we do a service to charity enlightened by truth, but we also help give credibility to truth, demonstrating its persuasive and authenticating power in the practical setting of social living. This is a matter of no small account today, in a social and cultural context which relativizes truth, often paying little heed to it and showing increasing reluctance to acknowledge its existence. (2)
I think what he's basically saying, (and I certainly believe it's true, though I never thought of it in quite this way before) is that our most powerful weapon against relativism is love. Wow.