In his famous argument for God’s existence, Saint Anselm of Canterbury began by defining and identifying God as “that than which nothing greater can be thought.” Several centuries later, Nicholas of Cusa reasoned from this starting point that, if so, God must also be that than which nothing lesser can be thought. As he argued:
[S]ince the absolutely Maximum is all that which can be, it is altogether actual. And just as there cannot be a greater, so for the same reason there cannot be a lesser, since it is all that which can be. But the Minimum is than than which there cannot be a lesser. And since the Maximum is also such, it is evident that the Minimum coincides with the Maximum. (On Learned Ignorance 1.4, trans. Hopkins)
God is so great, in other words, that he altogether transcends the very opposition between greater and lesser. Or put differently, in God the opposed relations of greater than and lesser than come full circle and converged onto each other. This is Cusa’s famous doctrine of the “coincidence of opposites.”
The Flame Imperishable 
Thus the Cross.
I think it is ridiculous for anyone, especially theologians, to assume that they have the right or individual power (including knowledge) to prove or disprove or even describe God’s Existence.
The truth is God, in His truth and essence, will never be known fully. I am sure there will come a time when He will reveal Himself but until that day comes God will always be the Mystery, the Mystery of the world which haunts our lives and causes us to question, to grow, to doubt, to search…
I also find it futile to try and ‘prove’ the existence of God. What is there to prove? There’s a lot of things we cannot prove – reality is different for every individual. The only proof of His existence, if anyone should venture into that territory, is that something inside of humans that makes them…human. Most people ignore it, but if you listen to it, nurture it, it is that quiet, still part of your being that feels something in the air, that sees something in the delicate, in the fragile, and the beautiful.