Some significant things here in terms of eating kosher (or not, as the text proves), but what strikes me is the idea of what comes out being what defines a person. That means the defilement is in me already. Sin is already taken root. I can't change that.
That is why self control is so important, although in really terrible at it. Really terrible. I can control some things (lent is an exercise in self control) but not all, and I do want what I want when I want it. I want things and don't get them and it makes me irrationally angry and upset. I get angry with God, really.
Is that sin? To want things? To not trust God? He was supposed to have given me these desires, but here it implies that is wrong. Well, desire isn't wrong exactly, but lust and coveting are. I'm not allowed to freely want. I suppose the real example I am thinking of right now is marriage. I want it, but God ignores that want. He doesn't care. So I guess that makes it sinful.
But how am I supposed to exercise self control when I want something so desperately? Every part of me craves it. It's not my fault God doesn't indulge this want. Am I only allowed to want things that get given to me? How am I supposed to make that call? When is a want that you crave so much wrong?
This isn't my fault. He is the one who isn't answering. So now I'm in sin, I guess. This could have all been averted. Hmph.