1. Some things undeniably exist (e.g., I cannot deny my own existence).
2. My nonexistence is possible.
3. Whatever has the possibility not to exist is currently caused to exist by another.
4. There cannot be an infinite regress of current causes of existence.
5. Therefore, a first uncaused cause of my current existence exists.
6. This uncaused cause must be infinite, unchanging, all-powerful, all-knowing, and all-perfect.
7. This infinitely perfect Being is appropriately called “God.”
8. Therefore, God exists.
9. This God who exists is identical to the God described in the Christian Scriptures.
10. Therefore, the God described in the Bible exists.
(Geisler, Norman L., Christian Apologetics, Grand Rapids, Michigan, Baker Book House , 1988, pp. 238-39)
This is just an outline, but it is an outline of an effective positive argument. A Non-Christian has the right to demand a defense of each of these premises, and I would welcome that discussion here.