Arcana Coelestia #9597
9597. 'With cherubs' means the Lord's watchfulness, guarding it from the approach of the hells and the harm they can do. This is clear from the meaning of 'cherubs' as watchfulness and providence, preventing any approach to the Lord except through good and protecting from harm the good from the Lord which exists in heaven and with man, dealt with in 9509, consequently guarding heaven from the approach of the hells and the harm they can do.
Jeremiah 51:15
15
He has made the earth by his power, he has established the world by his wisdom, and by his understanding has he stretched out the heavens: