11 I have been exhorting you, brethren, to this in such words, because the freedom of which our Lord Jesus Christ speaks belongs not to this present time. Look at what He added: “You shall be my disciples indeed; and you shall know the truth, and the truth shall set you free.” What means that— “shall set you free”? It shall make you freemen. In a word, the carnal, and fleshly-minded Jews— not those who had believed, but those in the crowd who believed not— thought that an injury was done them, because He said to them, “The truth shall make you free.” They were indignant at being designated as slaves. And slaves truly they were; and He explains to them what slavery it is, and what is that future freedom which is promised by Himself. But of this liberty and of that slavery it were too long to speak today.
Source: Tractates on the Gospel of John (New Advent)