In John 14:16, the Greek word for "The Comforter" was Paracletos (or parakletos).
The Muslim used this verse to prove the prophecy of their prophet Muhammad by twisting the term Paracletos as Periclytos, which means "praised one" or Ahmad in Arabic. Hence, Muhammad.
It should be a no brainer that the Islamic claim of corruption in Christian Greek text instead of theirs is ridiculous.