2 John
What do you really believe about Jesus?
If you don’t believe Jesus existed, you will likely pay no attention to His teaching or commands. He will have little or no influence on your life. It’s unlikely you would call yourself a Christian?
If you believe that Jesus existed, lived and was killed on a Roman cross for crimes he didn’t commit, you might respect Him. You might even be inspired by His life. You may live according to some of His teachings. You may or may not call yourself a Christian.