If there is only one G-d, why should G-d get jealous of someone worshipping any other g-d if they don't exist. Unless they do exist and thats why it gets G-d jealous. Thanks for your answer, James18

Answer:

G-d is not jealous of other gods. He is resentful of the worship of nothingness.

G-d despises foolishness.

G-d invested a lot into the Jewish People. He gave birth to them (when He took them out of the womb of Egypt), nurtured them (with miracles and manna) and educated them (with the Torah).

Then G-d turned to His now "grown" children and said "you are now mature and educated; futility is no longer acceptable".

It is precisely because of its nothingness that G-d is so intolerant of its worship.

This is analogous to a father who gives his son $100 to by groceries. An hour later the son comes home with $100 worth of jelly beans. Had his child come home with 2 Nintendo games the father would be upset, but understanding. But when his son spends $100 on jelly beans the father simply can't come to terms with it.

Especially when the son in question is 17.

Similarly G-d invested so much in the Jews. They are so capable. And He can't tolerate when they direct their hearts, souls, minds, and means, to a faux god.

The Talmud says the seal of G-d is Truth. G-d has no tolerance for fakes.

That is why G-d has no tolerance for the worship of something that isn't.