All things around us are either rest state or motion state.
A body is said to be rest if it does not change its position with respect to a fixed point taken as a reference point in its surroundings. For examples, a book lying on the table, if nobody disturb or replaced it then it remain at the same position in respect to time. That book said to be in a state rest.
A body is said to be in motion, if it changes its position with respect to a fixed point taken as a reference point in its surroundings. For examples, a walking man at park. That man changes his position in respect to time. Here the walking man is in motion state.
Consider you are in a moving train and the train cross a village, where a farmer standing on the field. Then anybody inside train considers that the farmer is in moving state and you are in rest state. Because according to him, the farmer is moving with respect to time and you remain in the same place in the train (as both of you are on the same train). But anybody outside the train other than that farmer considers that the farmer is in rest state and you are or the train is in motion state. Because with respect to that man train or you change the position in respect to time but the farmer is in the same position. That is why we can say rest state and motion state are a relative state.
If we consider a body (which is in rest state in earth) from a fixed position of outside the earth then we will look that body is moving rapidly with earth. Because earth itself moving surrounding the sun. that is why we can say nothing is in rest state in earth.