1) Every other religion begins with a man. Mohammed, Yoshke, Budda… the list goes on. One man had visions and revelations from ‘God’ and from there persuaded others. Never has there been a religion where 3.5 million people at once received the religion. You can date back every religion to the beginning. Jews have tradition up to Sinai [as a nation]. One cannot deny that there is a Torah, because if it was man-made, there would be no way of hoodwinking 3,000,000 people about it. They were all there.
2) Open up a Chumash. Learn through the Ramban and other rishonim and see the depth of their scientific knowledge – it was incredibly accurate. Books have been written about Science and the Gemoro — absolutely loads of proofs.
But have a look then at the Ba’al Haturim. There are some UNBELIEVEABLE surprises there. He goes through and finds the numerical values of words and matches them with others. The words of the verses and the numerical values of the interpretation is totally fantastic. How often does ??”?’s simple explanation fit word for word with the Ba’al Haturim? It is really fantastic.
No human could have done this. Every single letter and word in the Torah is calculated. There is absolutely NO WAY that it could have been conceived by mortal brain.
3) Read the Parsha about Shmitta, and the promises that were made to those who keep it. Then have a look at the videos about Kommemiyus — a huge locust plague ravaged the entire country, SKIPPING OVER the fields of those who kept SHMITA. Tens of irreligious who witnessed the miracles first hand returned to the religious path. That was no coincidence.
4) Torah Codes have been mentioned above.
Torah codes. Stuff like aids, wars, dates, names, events all near each other in appropriate places in the torah that are relevant to those events. For example you can find the name of every fruit or vegetable in breishis via torah codes. Or stuff like the first person who discovered aids, name, year etc, in the torah. Many people say that “yea sure anyone can take a giant book and find torah codes but the fact is that the chances of finding a “code” in other books without messing up the whole story in it is as likely as 1000 monkeys bashing a typewriter and eventually coming up with shakespear. Or a tornado coming over a house and restructuring it into an airplane. If the torah had only a handful of torah codes then you could say yes ok it was just chance. But to find thousands and thousands of them with the story still intact is impossible in any other book no matter how large it is.
Google ‘Torah Codes’, and have a look at a few of the examples.
5) Speak to anybody who has been learning in a Yeshiva – ‘Iyun’ seder – where yeshiva bochurim learn into the depth of the Gemara. There is no better proof than finishing ten blatt (pages) of Gemara properly, with the Rishonim and Achronim.