What is the origin of the idiom "in seventh heaven" and when to use it?

The origin of the phrase "in seventh heaven" can be traced back to ancient religious beliefs and numerology. In many religious traditions, the number seven is considered sacred and represents perfection or completeness. In this context, being in the seventh heaven would mean being in the highest or most perfect state of happiness. This idiom is typically used in various situations where someone wants to express a state of extreme happiness or delight.