1
general::
In a state of bliss, as in John was in seventh heaven when the director praised his speech. Used figuratively since the early 1800s, this term alludes to the dwelling place of God in highest of the seven concentric spheres that surround the earth in the system recognized by both Muslims and ancient Jews.
American Heritage Idioms
2
general::
Phrase(s): in seventh heaven
Fig. in a very happy state. • Ann was really in seventh heaven when she got a car of her own. • I’d be in seventh heaven if I had a million dollars.
McGrawhill's American Idioms And Phrasal Verbs