Since they could not find a way to bring him in because of the crowd, they went up on the roof and lowered him on the mat through the roof tiles into the middle of the crowd before Jesus.
The houses of Jerusalem and the houses of the kings of Judah will become impure like that place Topheth — all the houses on whose rooftops they have burned incense to the whole heavenly host and poured out drink offerings to other gods.”
Since they were not able to bring him to Jesus because of the crowd, they removed the roof above where He was. And when they had broken through, they lowered the mat on which the paralytic was lying.