The burning bush is also the symbol of the Presbyterian Church of Scotland. Their motto is "Burning, but not consumed" That's good, too.
The Presbyterian Church of Ireland (Northern Ireland Protties, don't you know!) also uses the burning bush on its flag. That motto is "Burning, but flourishing"
I like all of those. The Presby Church in America has never used the burning bush, which is a little odd, since Scotch-Irish Presbies abound here. But we do have that little bit of fire on each side of the cross in our symbol. I think it is supposed to be the tongues of flame from Pentecost. But I'm going to pretend it is the burning-but-not-burning-up-bush.
On fire, and never burned out. That would be a great church motto.