What Is My Religion? I Feel Shame on My Self because am a Muslim

Once I ask a question to my Teacher (Mulla) in the Mosque, What is the difference in the Muslim and the Non-Muslim?

He Replied One who beleaves on ALLAH and prophet MUHAMMAD P.B.U.H is a Muslim and One who does not beleave on ALLAH and MUHAMMAD P.B.U.H is a Non-Muslim.

I ask Again, So what we do? How we teach the Non-Muslim?

He replied Just Kill him.