How to mesh squre block with a spherical particle inside

I have a squre block and inside it there is an sphere. I want to mesh the whole assembly. I can mesh the sphere but when i try to mesh the squre block with the spherical hole it cant mesh and says "it cant select the source and target face". I also tried to devide it into 8 parts. That helped me to mesh the sphere but i cant mesh the squre with spherical hole with that too. So please anyone can help me out.