Arcana Coelestia#1688
1688. That 'the valley of Siddim was pits after pits - or was full of pits - of bitumen' means the uncleanness of falsities and evil desires is clear from the meaning of 'Siddim' as uncleanness, dealt with above at verse 3, and also from the meaning of 'pits' as falsities, and of 'bitumen' as evil desires. Falsities are called 'pits' on account of the filthy water these contain, and evil desires are called 'bitumen' on account of the foul sulphurous stench of such water.
עברים 7:3
3
באין אב באין אם באין יחש ולימיו אין תחלה ולחייו אין סוף כי אם נדמה לבן האלהים הוא עומד בכהנתו לנצח׃