The short answer is no. The long answer?
As I note in this post, we can mix water soluble things with water soluble things and oil soluble things with oil soluble things. We can only mix a water soluble thing with an oil soluble thing if we have an emulsifier. Glycerin is a water soluble ingredient and a body bar - which I'm guessing is a lotion bar of some kind - is anhydrous, so the two can't be used together without some kind of emulsifier.
If you wanted to add glycerin to a lotion bar, you would need an emulsifier, like Polawax, Incroquat BTMS-50, Ritamulse SCG, and so on. You can see an example of a bar like this in my pumpkin seed oil body scrub bar. Because I have included Ritamulse SCG, I can include water soluble ingredients like a hydrolyzed protein or glycerin.
You might see people adding water soluble ingredients to anhydrous products without an emulsifier. For instance, adding honey to a lip balm. I added sodium lactate to this lip balm a few years ago. How? I used lecithin, which can emulsify small amounts of water soluble ingredients into things like a lip balm or a lotion bar.