You beat me to the post.
We must not put God to the proof. (Even if that was a convenient and lazy way to impress folks who would happily worship a wind-up doll god that performs for atheists on command.)
I wouldn't worship a lower case "g" god that fits in my top pocket like a fob watch on a chain, that I can instantly pull out and show to anyone and everyone who demands proof that I actually have a god in my pocket.
...Should you ever run into this canard, refer your friend to the 18th chapter of I Kings, in which Jehovah shows up in a contest with Baal, as proposed by Elijah to show a crowd of pagans that his god is real and can light a fire. Jehovah comes through and lights a tremendous fire, while the nonexistent Baal pussies out. Jehovah's fire even burns the stones and dirt around the burnt offering...
Oh you poor thing.
You think 1st Kings 18 is God performing on demand?
Did you not read who commanded Elijah to go and smack down Ahab?
God wasn't asked to do something by Elijah.
It was the other way around.
Go back and read it again. It's Gods prerogative to send people a sign.
And no Christian I know would ever say God never proves His own power with signs and wonders.
By the way, add this to your list of bible 'gotcha' verses.
God also testified to it by signs, wonders and various miracles, and by gifts of the Holy Spirit distributed according to his will.
Hebrews 2:4