يَوْمَ تَرْجُفُ الاَْرْضُ وَالْجِبَالُand a painful torment. On the Day when the earth and the mountains will (Tarjuf) shake,meaning, they will quake.وَكَانَتِ الْجِبَالُ كَثِيبًا مَّهِيلًAnd the mountains will be a heap of sand poured out.meaning, they will become like hills of sand after they had been firm rocks. Then they will be utterly destroyed and nothing will remain of them. This will occur until the entire earth becomes a flat land and no curvature will be seen in it. Thus, there will be no valleys and no hills. This means that no part of it will be low or elevated.Your Messenger is like the Messenger to Fir`awn, and You know what happened to Fir`awn Then addresses the disbelievers of the Quraysh, and along with them the rest of mankind