What would you consider to be evidence for God?

[Athene]

I feel that actually witnessing a miracle firsthand would make me reconsider the possibility of the existence of a god. A miracle, to my understanding is not an occurrence that is just highly improbable or statistically unlikely. Another person's account of of a divine experience or miraculous event, is not something I would be able to consider.
If I were to witness something truly impossible happen with my own to eyes, I would be likely to consider there could be a force or forces operating outside  the laws of physics, nature, etc.

The problem is that if you witness something, and it really happened rather than being a hallucination or whatever, then it isn't impossible It just runs contrary to what we thought was possible.

Right. Including a god, perhaps.

I don't have a belief in the existence God, because I don't believe it's possible.
If I were to witness the truly impossible, become possible, it stands to reason that the experience would challenge me to question the very idea what's possible in general. Possibly.