By default, Camera Raw and Lightroom set a sharpening Amount of 40, Radius 1.0 and Detail 25 to all raw images: a base-level starting point for further sharpening.
Digital images are inherently soft, so they need some level of sharpening just to make them appear acceptable. If your camera is set to shoot in JPEG, the initial sharpening takes place in-camera. By contrast, with raw files you need to do your own initial sharpening. This is sometimes called Capture Sharpening, as it happens at the start of a workflow (as opposed to Output Sharpening, which happens at the end, after an image has been resized for print or web). Capture Sharpening usually takes place in your chosen raw editor, like the Detail Panel within Lightroom or Photoshop’s Camera Raw plugin.