But obviously God himself could change this, so his point stands.
ie
You: So God, can I wear mixed fibres?
God: of course! Why would I care?
You: aha! You're not God at all! The bible warns against mixed fibres!
God: oh, for heaven's sake - i wish those idiots hadnt put that in - they literally pulled that bit out of their collective asses!
You: .....
In order for that to work, the Bible has to be in question, which means whatever god he is, the God of the Bible he is not.