To prove the real existence of God (or any other being for that matter), one simply just needs to believe. Believe in your heart.
SmartAZ said: "Stop trying to prove or disprove spiritual things with science." This has NOT happened. No one is trying to prove anything.
Spirits do NOT need to reveal themselves to us in regards to the spirit realm. If we can feel it then it's there.
SmartAZ spouts the word "Christian" and even provides a chapter in Proverbs followed by Romans and Thessalonians. I find it ridiculous for SmartAZ to even mention this since the question clearly states "many religions", not just one. w
Not everyone is Christian. Some are Jewish, Muslim and even Wiccan (like me). Those of different religions believe in different Gods (Muslims believe in Allah, Wiccan's believe in The God (Green Man) and The Goddess (Lady Earth).
How we choose to believe all comes from within. Nothing needs to be seen to prove it.