Based on my view, the fundamental particle of matter moves at the speed 'c'. So any body made up of such particles will always be moving; however, part of the energy remains as internal energy, and so no body attains the speed of light. To keep a body at rest, force has to be applied. But the body will resist this, and this will create a potential state in the body. So it is impossible to keep a body at rest. As pointed out earlier, the bodies at rest on earth are moving at a very high speed along with the galaxy-cluster.