This verse shows the determination of the friends of a disable man to get him to Jesus for healing. They brought their friends in a blanket or pallet to the house where Jesus was teaching. Unable to get into the building because of the crowd, they climbed an exterior stairway to the roof. After ripping a hole in the roof, they lowered him down to Jesus.
The roofs of the most houses in the Bible times were built in three simple steps. First, beams or logs were laid across the tops of the exterior walls. These beams were then overlaid with thatch, consisting of tree branches and straw. Finally, that thatch was topped with a layer of clay that was hardened in the sun. In a climate in which rainfall was minimal, these roofs would hold up well if the clay was rolled and hardened on a regular basis.
Tearing through a roof like this was a simple matter. It was also easy to repair.
MARK 2:4 – They [four friends of the paralyzed man] uncovered the roof where he [Jesus] was: and when they had broken it up, they let down the bed wherein the sick of the palsy [paralyzed man NIV] lay.