Isaiah 57:8

and behind the posts of thy door thou didst place thy memorials. Didst thou think that if thou shouldest depart from me, thou wouldest gain? thou hast loved those that lay with thee;

Behind the doors also and the posts hast thou set up thy remembrance: for thou hast discovered thyself to another than me, and art gone up; thou hast enlarged thy bed, and made thee a covenant with them; thou lovedst their bed where thou sawest it.

You have set up your memorial behind the doors and the posts, for you have exposed yourself to someone besides me, and have gone up. You have enlarged your bed and made a covenant for yourself with them. You loved what you saw on their bed.