What is Blasphemy against the Holy Spirit?

Some people say it is only when you say God gets his powers from the devil. Some people say it's when you stop believing in Christ. Some people say that if you leave chirst because you like another religion, that's blasmeny even when you repented and went back to Him. Some people say you can't just sit down and commit it, it can only be commit long term. Some say as long as you don't say it with your mouth, you didn't commit it. I'm so confused what exactly is blasmeny against the Holy Spirit?