I believe that when one talks about “belief” in God that it is important to actually know what that actually means. Can one who has not studied Judaism in a traditional and serious manner really think or say that he doesn’t believe in Judaism? I have heard people say, “I don’t believe in God” when they haven’t even bothered to explore what “God” means in Judaism. How can one not believe in something without really knowing what it is that he claims he doesn’t believe in?
I empathize with your desire about proof for God's existence. I personally find the strongest proof that there is one God who created the world, took the Jewish People out of Egyptian slavery and gave us the Torah at Mt. Sinai. The same Torah we have today. It has kept us as the same nation we were more than 3,000 years ago, despite the exiles, destructions and the Holocaust. Look at the way in which the Torah was given to an entire nation "in person" (Deut. ch. 5). The Torah teaches about the Creation along with everything necessary for life in this world and the next.
This Sinai experience has been passed down from parent to child, from generation to generation until today. It is the same history and teachings that are transmitted yearly at the Passover Seder, and daily in study halls throughout the world. This is the testimony of an entire people to the truth that they experienced thousands of years ago that there is one God who created the world, Mankind, gave us the Torah and is eternal.
Perhaps you would allow me to suggest that you try a Gateways retreat. The classes and the retreats offered by Gateways are excellent and cater to all ages and religious observance in an appealing and “non-threatening” way. Perhaps you could try looking at what they have to offer on their site: www.gatewaysonline.org
I also think that you might enjoy reading one of the classic books of Jewish philosophy called the Kuzari which is a book written almost a thousand years ago by Rabbi Yehudah Halevy in the form of a dialog between a Rabbi and a Gentile king. It is theological debate between a Greek philosopher, a Christian, a Muslim and, finally a Jew. It is truly fascinating. There is an excellent new translation (with footnotes) by Feldheim Press that ought to be easily available.
