My knower. Explain how you know you exist. You can't - you just know. That my knower. And my knower tells me various things: God exists...and I'm going to see him - irrespective of my behaviour. My knower also tells me that if I consider his grace unto me cheaply, casually, start of Romans 6-edly, then his discipline I can expect - unto 'sleep' (physical death). It stands to reason. My reason (his reason in fact what with him living in me).
How do you get from knowing you exist--which indeed you do know--to knowing God exists?