Weakness
Todays sermon was interesting. If focused on the Weakness of God that saves us. It's not a phrase we think about: The weakness of God. It's right there in 1 Corinthians 1:25:
For God's foolishness is wiser than human wisdom, and God's weakness is stronger than human strength.
I think this points towards a theistic definition or understanding of God, but that's all we really have. I know Spong has rejected the theistic imagry of God, but I'm not sure that the average Joe or Jane could think about God without the theistic images.