Augustine of Hippo — as excerpted in the Catena Aurea on John 16:16-22

“(Tr. ci. 5) This fruit indeed the Church now yearneth for in travail, but then will enjoy in her delivery. And it is a male child, because all active duties are for the sake of devotion; for that only is free which is desired for its own sake, not for any thing else, and action is for this end. This is the end which satisfies and is eternal: for nothing can satisfy but what is itself the ultimate end. Wherefore of them it is well said, Your joy no man taketh from you.”