We are able to walk because of the friction present between our feet and the ground. In order to walk, we push the ground in the backward direction with our feet. The force of friction pushes it in the forward direction and allows us to walk.
The force of friction between the ground and feet decreases when there is soapy water spilled on the floor as it acts as a lubricant.
Hence, it becomes difficult to walk on the soapy floor.