Q: What did Jesus mean when He said Capernaum would be “brought down” to Hades?

A: Let's get the larger context of what was stated:

“Woe unto thee, Chorazin! Woe unto thee, Bethsaida! [woe is simply the English substitute for the actual expression, Oy! found in the original. Oy! denotes its Jewish character] for if the mighty works, which were done in you, had been done in Tyre and Sidon, they would have repented long ago in sackcloth and ashes. But I say unto you, It shall be more tolerable for Tyre and Sidon at the day of judgment, than for you. And thou, Capernaum, which art exalted unto heaven, shalt be brought down to hell: for if the mighty works, which have been done in thee, had been done in Sodom, it would have remained until this day. But I say unto you, That it shall be more tolerable for the land of Sodom in the day of judgment, than for thee” (Matthew 11:21-24).

As we have indicated before, all that pertains to books of Matthew, Mark, Luke, John, James and the writings of Peter, have to do with the literal, physical kingdom of heaven that is going to be established on the earth in Jerusalem. None of their writings have anything to do with our citizenship and place in heaven. Believing Jews are not destined for heaven, their place is upon the earth. Believers of Paul's evangel are not going to be in the earth-bound kingdom of heaven nor have a place there. These are separate blessings. But the churches disbelieve and deny this truth. They've been picking and choosing only what they want from the Scriptures for centuries, and that isn't going to change. That is why Christ calls us out from them and wants us to be separate from them (II Corinthians 6:14-18).

Capernaum saw the mighty works of Christ, and yet they denied Him! Christ was speaking of the judgment to come in 70 A.D. For Capernaum, the realization of what they had in their midst, and what could have been, were more intolerable than the consequences that accompanied the original mistake. Being brought down to hell [Hades] is just an earlier way of expressing complete ruin, that's all. It is not a reference to the mythical fiery hell of religious tradition. Capernaum, as well as Israel were ruined for denying their Messiah. Their day of judgment was their being blinded to the truth, and their destruction by Rome in 70 A.D.