Not at all, if that's what your body needs. Particularly when first starting a workout routine, your body is going to need slightly longer to properly recover from training, and sometimes two days of full rest is necessary. You don't necessarily need to rest your entire body for two days straight, though. You can rest a certain muscle group by training other ones for a couple of days, before returning to it. Generally, you only need one rest day at a time, though it's always best to listen to your body.