why is oil so important to the

countries of the arabian peninsula?

3 answers

Arabia produces much of the world's oil; in Saudi Arabia, oil profits are a large part if the economy. Check these sites for details.

https://www.cia.gov/library/publications/the-world-factbook/geos/sa.html#Econ

http://www.country-studies.com/saudi-arabia/oil-industry.html
i understand but other websites don't tell me a lot about WHY it is important.
Because it's there.

Because they have so much of it, and other countries (US included) consume so much. The higher the demand, the higher the prices that can be charged.