The God of Moses doesn’t need to complete with other religions because he’s the only living God. All the other gods are fakes, total inventions, because they have never done anything in history nor do they respond to prayer.
So a human being has basically one of two options: Either believe in the living God, or believe in nothing. Believing in some ancient pagan god is about as useless as believing in the tooth fairy. A pagan god is not going to do anything for you.
So why should you believe in the living God? Because he is the only one that can give you eternal life. That is his promise. If you follow the plan taught by Jesus, you are guaranteed eternal life. How do I know that? Because he said so.
John 6: “Jesus declared, “… whoever comes to me I will never drive away. For I have come down from heaven not to do my will but to do the will of him who sent me. For my Father’s will is that everyone who looks to the Son and believes in him shall have eternal life, and I will raise them up at the last day.”
How can someone know if Jesus is real? That’s pretty easy because Jesus claimed to be God and raised himself up from the dead to prove it. No other person in history has been able to do that. Not only that, Jesus raised a man, Lazarus, after he was dead for 4 days. No one can do that either. He did that only to prove to humanity he has the power to raise people from the dead.
If you are skeptical, consider this: Thousands of people saw Jesus die on the cross. And thousands of people saw him alive after he was resurrected from the dead. Hundreds of early Christians were tortured to death for following their faith and proclaiming Jesus as their Lord. Do you really think they would do that just for a hoax?
Oh yes, that thing about God killing people. Actually, he’s not keen on killing them, in fact, he wants everyone to have eternal life. God has bent over backwards to give people eternal life, but if they persist in worshiping the Golden Calf and burning up their children alive as sacrifices to Baal, then God has no other choice than to destroy those people. God only tolerates evil for a limited time, so when people have been warned repeatedly, over hundreds of years, and yet they continue to ignore the warnings, God has no other option left but to destroy them. But it pains him just the same.